Tropical Diseases/Chapter 46
Section VI. SKIN DISEASES
CHAPTER XLVI
1. NON-SPECIFIC SKIN DISEASES
PRICKLY HEAT
Prickly heat, or, as it is sometimes called, lichen tropicus, is probably a form of miliaria (not of lichen) connected with the excessive sweating incident to the heat of tropical climates. According to Pollitzer, the mechanism of its production depends on the non-cornification of the cells of the stratum corneum, the individual cells of which, in consequence of their being sodden by constant perspiration, swell and so obstruct the orifices of the sweat-glands, thereby leading to accumulation of sweat in the ducts. Pearse regards the disease as an acute distension of the sebaceous glands by their own secretion; the glands, he holds, are over-stimulated in order to supply an adequate amount of sebum to the skin, so as to make up for the loss of that material washed away by inordinate sweating. Durham regards prickly heat as an infective disease produced by a minute and very active amœba, readily found in the fluid of the vesicles provided search is made before the contents become turbid.
Nearly every European in the tropics suffers from prickly heat, particularly during the earlier years of residence. Some never seem to become acclimatized in this respect, but continue year after year to exhibit their crop of prickly heat lesions when the hot season comes round.
Though sufficiently annoying in the robust and healthy, in them prickly heat is not a grave affair. It is otherwise in the case of the invalid, of delicate sickly children, of hysterical and, especially, of parturient women; to these it may prove, by interfering with sleep and provoking restlessness, a very serious matter. Prickly heat is also a common though indirect cause of boils; for the breaches of surface, following on the scratching it induces, afford many opportunities for the invasion of the micro-organisms of furuncular disease.
Prickly heat consists of a miliary-like eruption, generally most profuse on those parts of the body, as around the waist, which are closely covered with clothing; but it also occurs on the backs of the hands, arms, legs, forehead, occasionally on the face, the scalp, in fact on any part of the surface of the body except the palms and soles. The minute, shining, glass-like vesicles, and the numerous, closely set and slightly inflamed papules, give the skin the feeling as if thickly sprinkled with grains of sand. The eruption may keep out for months on end, becoming better or worse according to circumstances. The pricking and itching are often exceedingly distressing. Anything leading to perspiration immediately provokes an out-burst of this almost intolerable itching— nothing more certainly than a cup of hot tea or a plate of hot soup. Long drinks, exposure to the hot sun, close rooms, warm clothing, all aggravate the distress. Sometimes the little vesicles may pustulate, doubtless from micrococcus infection. So soon as the weather becomes cool the eruption and the irritation quickly subside.
Treatment.— Manifestly the most important thing is the avoidance of all causes of perspiration —particularly the copious consumption of fluids, especially hot fluids— moderation in exercise, avoiding sea bathing, close rooms, warm clothing, and so forth. Soap should not be used in the bath. The sleeping-mattress and pillow should be covered with a finely woven grass mat, and the bed provided with what is known in the East as a " Dutch-wife "— that is, a hollow cylinder, 4 ft. by 8 or 10 in., of open rattan' work, over which the arms and legs can be thrown, and unnecessary apposition of sweating surfaces so avoided. A punkah at night is a great comfort. Many things have been recommended as preventives; for example, rubbing the body over after the bath with the juice of a lemon, Jeyes' fluid or bran in the bath, etc. Every bath-room in the tropics should be provided with some mildly astringent and antiseptic dusting powder. A very good one consists of equal parts of boric acid, oxide of zinc, and starch. This should be freely applied, after careful drying of the skin, particularly to the axillæ, crutch, under the mammæ in women, and between the folds of skin in fat children and adults. A simple precaution of this sort saves much suffering both from prickly heat and epiphytic skin disease.
Durham recommends painting the patches with weak iodine or, better, rubbing in solution of corrosive sublimate, 1 in 500 to 1 in 1,000: this he found very efficacious, curing the disease with certainty after one or two applications. He suggests the use of some form of obstetric soap as being less liable to lead, through inadvertence, to accidental poisoning.
Castellani advises the frequent application of a salicylic acid (51) and spirit (^viii) lotion. Pearse strongly recommends the inunction of a mixture of almond oil and lanolin in the proportion of 8 to 1, and scented according to fancy. St. George Gray finds thin flannel a better wear than cotton or linen as a preventive of prickly heat. Sometimes the following powder, gently rubbed in for five or ten minutes with a damp sponge, cures bad patches of prickly heat: Sublimed sulphur, 80 parts; magnesia, 15 parts; oxide of zinc, 5 parts. Lotions of calamine, with or without hydrocyanic acid, or of carbolic acid, relieve the itching temporarily.
2. BACTERIAL SKIN DISEASES
TROPICAL SLOUGHING PHAGEDÆNA
Definition.— A rapidly spreading but, as a rule, after a time, spontaneously arrested gangrene of the skin and subjacent tissues, resulting in the formation of a large sloughing sore. Though occasionally fatal, these sores almost always, under favourable conditions, granulate and cicatrize, or become chronic ulcers.
Geographical distribution.—Sloughing phagedæna is common in most tropical countries, particularly in those with a hot, damp climate. These sores are often named after those districts in which they are specially prevalent; thus we hear of Mozambique ulcer, Yemen ulcer, etc. They are found principally in jungle lands, less frequently in towns and well-settled districts. Whether tropical sloughing phagedæna and hospital gangrene, at one time so prevalent in the hospitals of Europe, are the same disease, it is difficult to say. They agree in some respects; but in the marked tendency of the tropical sore to self-limitation, and, possibly, as Scheube points out, in its relatively feebly infective power, there is some indication of a specific difference.
Occasionally this disease assumes epidemic proportions. Thus, Lloyd Patterson (Ind. Med. Gaz., Nov., 1908) described one such epidemic which "swept like a plague up the whole of Assam," seriously interfering with the efficiency of the labour force on the tea plantations.
A variety of bacteria and spirochætes have been described as possible germ causes of this disease. Vincent remarked the frequent concurrence of spirochætes and fusiform bacilli in the sores, an observation confirmed by several others, including Todd and Wolbach on the Gambia. Prowazek attributes these ulcers to Spirochœta, schaudinni. Lloyd Patterson has called attention (loc. cit.) to a bacillus occurring in scrapings from the base of the ulcers, which he considers as the probable germ, and which had hitherto been overlooked in consequence of the difficulty in staining it, prolonged immersion in Leishman's stain being necessary.
Although sloughing phagedæna is evidently a germ disease, it is not readily communicated by ordinary inoculation either to man or to the lower animals. Apparently a concurrence of certain unknown conditions is essential. Lloyd Patterson, however, by bandaging a swab smeared with discharge from a typical sore (discharge containing large numbers of his bacillus) on to the surface of an abrasion from which the scab had been removed, succeeded in producing a characteristic sore, in the discharge from which his bacillus was present in great profusion.
Etiology.—Doubtless depending on the proliferation in the affected tissues of some specific micro-organism, not yet satisfactorily separated, the germ of sloughing phagedæna attacks the healthy as well as the debilitated, young or old, male or female. It finds its special opportunity in the bodies of men who, from overwork, underfeeding, exposure, malaria, dysentery, scorbutus, and the like, are physically depressed. Thus it is apt to attack the half-starved, malaria-stricken pioneers in jungle lands, overdriven slave gangs, and soldiers campaigning in the tropics. In such circumstances a slight wound, an abrasion, even an insect bite, or an old chronic ulcer may serve as the starting-point for one of these terrible sores. Where yaws and sloughing phagedæna are co-endemic, the sores of the former may become infected with the virus of the latter, and serious sloughing and cicatricial contractions result. The feet and legs, being most exposed to injury, are the most frequent locations for this form of ulceration; but the arms or any other part of the body may also be attacked.
Symptoms.—If the disease occur in previously sound skin the first indication is the formation of a larger or smaller bleb with sero-sanguinolent contents. The formation of this may be attended with some pain and constitutional irritation. When, in the course of a few hours, the bulla ruptures, an ash-grey, moist slough is exposed. The sloughing process rapidly extends in all directions until the skin and subcutaneous fascia over an area of an inch to many inches in diameter are converted into a yellowish, moist, horribly stinking slough. After a few days the centre of the slough beings to liquefy, the sore still continuing to extend at the periphery. In the course of a week or longer the sloughing process may cease and the slough be gradually thrown off. Then it is seen that not only have the skin and superficial fascia been destroyed, but that in bad cases possibly muscles, tendons, nerves, vessels, and even the periosteum of the bones, have shared in the gangrenous process. Fortunately in many instances the deeper structures are spared, the disease being relatively limited and superficial. Sometimes, however, important structures, including joints, bones, and large blood-vessels, are destroyed; in such cases, even if life be spared, great deformity may ensue from different forms of ankylosis, or from strangulation of a distal part by a contracting cicatrix.
When the disease attacks a pre-existing wound or sore, the granulating surface of this becomes dry, and rapidly assumes the appearance and characters of a slough.
In sloughing phagedæna the neighbourhood of the sore is somewhat congested and swollen, particularly so if the patient has been obliged to use the limb. Constitutional disturbance may be considerable and of an adynamic type. On the other hand, it occasionally happens that large sores are attended with singularly slight local or general reaction. In bad cases a sapræmic condition is apt to supervene and carry off the patient; or death may occur from bleeding from the opening of a large blood-vessel.
Treatment.—It is of the first importance to endeavour to correct any cachectic state which may be present. Thus good food, fresh vegetables, lime-juice, and quinine are almost invariably indicated. Opium in full doses, not merely to assuage pain, but on account of its special action on the phagedænic process, is usually of great service. Locally, an endeavour must be made effectually to destroy the germ by the application of some powerful and penetrating caustic to the diseased surface. With this view, on the strength of considerable experience, I recommend that the patient be put under chloroform and the slough thoroughly dissolved off by the free application of pure carbolic acid, a piece of lint on a stout stick being used as a mop for the purpose. Thereafter the limb should be elevated and placed under some improvised irrigator from which a weak, warm antiseptic solution should continuously trickle over the now clean surface. If the phagedænic action recur the carbolic acid must be promptly reapplied as often as may be necessary. On healthy granulations springing up the nicer is to be treated on ordinary principles. Lloyd Patterson recommends a dressing of carbolic oil after the initial cauterization, and subsequently, when the sore is clean, a dressing of lead-foil such as is used for lining tea-chests. Patients with this disease should be regarded as infective, and, so far as possible, isolated.
Boils
The anatomical and clinical features of this painful affection are too familiar to require detailed description. Suffice it to say that a boil is produced by the proliferation of Staphylococcus pyogenes aureus and albus, Streptococcus pyogenes, or other pyogenic micro-organisms in the skin and subcutaneous tissue; that the organism gives rise to local and limited infiltration of the tissues with lymph which subsequently and rapidly dies, the necrotic core being surrounded by an areola of acute inflammation; that this core is separated by a process of sloughing and so got rid of, the resulting ulcer speedily healing and leaving a depressed scar, which, when occurring about the legs, may become pigmented. Though a self-limiting disease locally, it is nevertheless capable of being inoculated elsewhere in the same individual, both through a breach of surface and, also, by simple contact of the discharges with the skin, the micro-organism apparently entering by a hair follicle. This auto-inoculability of boils is apt to be overlooked.
Conditions of debility, presumably by lowering resistance, predispose to boils; the subjects of diabetes are specially prone to them, the saccharine state of the blood or secretions seeming to be particularly favourable to growth of the specific germ.
Few Europeans in the tropics escape an attack of boils at one time or another. In some instances crop after crop succeed one another, the individual boils being so numerous that the patient is quite unfitted for work by the attendant pain and fever. In certain years so many members of a community are attacked that the disease may be described as being epidemic. These epidemics, occurring when some particular fruit is in season, are very generally, but probably incorrectly, attributed to the use of the fruit in question. Mangoes, probably erroneously, are frequently held responsible.
Treatment.— Any constitutional irregularity must be treated appropriately. Malaria demands quinine; anæmia and debility, iron and wine; constipation, aperients; diabetes, a suitable diet. I have never seen any good from such vaunted specifics as calcium sulphuret, tar water, or yeast.
Boils ought never, unless in very exceptional circumstances, to be poulticed. Poulticing, although it may relieve the pain of the existing boil, is prone to be followed by more boils in the area sodden by the heat and moisture. Neither should boils be incised or squeezed. The only exception to the rule for not cutting is in the case of boils occurring in the scalp or in the axilla. In the former situation, unless opened early, they are apt, especially in young children, to burrow and cause troublesome abscesses; in the latter situation boils tend to be very indolent and painful, and do not readily spontaneously break through the lax integuments.
In any situation in which the boil is liable to be irritated by pressure or clothing, it is sometimes a good plan to cover the part with a circle of wash-leather spread with soap plaster, and having a small hole cut in its centre corresponding to the apex of the boil. When a boil opens, the discharge must be kept from soiling the adjoining skin, and the patient must be warned against touching the skin elsewhere with pus-soiled fingers. The parts must be frequently cleansed with l-in-1,000 corrosive sublimate lotion, powdered with boric acid and covered with a dry, absorbent antiseptic dressing. A threatening boil may - often be aborted by touching the little initial itching or vesiculated papule with some penetrating antiseptic, as iodine tincture, or by painting it with collodion. A very successful method is to drill slowly into the centre of the papule with a pointed pencil of hard wood dipped in pure carbolic acid. The point of the pencil should penetrate at least an eighth of an inch, and should be frequently recharged with the acid during the drilling process; the pain is trifling. In this way, in a severe attack of furunculosis, boil after boil may be aborted and the attack brought to an end. In obstinate chronic furunculosis excellent results have occasionally attended treatment conducted on Wright's method of exalting the opsonic index of the blood by injections of killed cultures of the patient's pyogenic micro-organisms.
In severe cases change of air may be necessary.
PEMPHIGUS CONTAGIOSUS (PYOSIS MANSONI: Castellani and Chalmers)
Definition.— A non-febrile, highly contagious skin disease peculiar to warm countries. It is characterized by the formation of large vesicles or bullæ which are unattended by marked inflammation, ulceration, or the formation of crusts or scars.
Geographical distribution.— Pemphigus contagiosus is very common in South China during the hot weather; in some years it may even be described as epidemic. It is perennial in the Straits Settlements, and it is known in Ceylon, Madras, in North Queensland, Japan, and America. Doubtless, although it has escaped notice by most medical writers, it is common enough elsewhere in the tropics, or wherever heat and moisture combine to bring about a state of skin favouring its development on the infective material being applied. It is especially common in schools and similar institutions where large numbers of children are thrown much together; they readily pass the disease one to the other. European children are more prone to it than native children; European adults are by no means exempt, but the native adult is rarely affected.
Symptoms.— Pemphigus contagiosus closely resembles certain forms of the impetigo contagiosa of temperate countries, and is doubtless a variety of this class of skin disease. The individual lesions, as can readily be ascertained by inoculation experiments, begin as minute erythematous specks, which rapidly proceed to the formation of vesicles, bullæ, or even large pemphigus-like blebs. The little blister springs abruptly from sound skin; there is no, or very little, areola of congestion. For a short time the hemispherical bleb is beautifully pellucid, tense, and shining. Presently the serous contents become some-what turbid, and the blister gets flaccid and dull. At this stage, from scratching or from pressure, the blister is generally ruptured. The morbid process does not at once come to an end, but proceeds as an advancing, eccentrically spreading exfoliation of the epidermis; an exfoliation which may not cease to advance until an area an inch or more in diameter is denuded of epithelium. Then, in that particular spot, the disease stops, a pinkish, slightly glazed-looking patch, rarely covered with a tissue-paper-like scale, remaining for some time. Occasionally, after the rupture of the primary bleb, vesication may continue in the peripheral portion of its remains. Only one or two blebs may be visible on the entire surface of the body; generally there are many, the disease being spread by the fingers in scratching or rubbing.
Pemphigus contagiosus may occur in almost any part of the body. In young children it is usually diffuse; in adults it is mostly confined to the axillæ and crutch. In these situations it gives rise to much irritation and discomfort, owing to the successive crops of bullse running into each other and rendering the parts raw and tender, and predisposed to boils or some form of eczematous intertrigo. During warm, moist weather it nray be kept up indefinitely by auto-inoculation.
Assistant- Surgeon Soorjee Narain Singh describes a series of cases of a form of contagious pemphigus occurring in rapid succession in the children of three families in India (exact locality not specified), which bears some resemblance to the pemphigus contagiosus above described. It differs, however, inasmuch as in the Indian disease the bullae were very large— often larger than hen's eggs— and persisted for from one to three weeks. In one of the thirteen cases described there followed a certain amount of sloughing at the seat of the bullæ; in the others there was neither ulceration nor constitutional disturbance.
Etiology and pathology.— Like ordinary impetigo contagiosa, this is undoubtedly a germ disease. I have found a diplococcns in the epidermis and fluid of the blister; whether this is the special bacterium responsible for the disease, cultivation and inoculation experiment have not yet decided. The Leishman body has been found in the contents of the blebs. Its presence there has probably no etiological significance so far as this special lesion is concerned.
Diagnosis.— Absence of constitutional symptoms, or a history of such, distinguishes pemphigus contagiosus from chicken-pox. Absence of trichophyton elements and of a well-defined, slightly raised, festooned, and itching margin, together with the presence of large blebs and scaling of the epidermis, distinguish it from ordinary forms of body ringworm— a disease with which, when occurring in the armpits and crutch in adults, it is frequently confounded.
Treatment.— Cleanliness, the frequent use of a bichloride of mercury lotion (1 to 1,000), and a dusting powder of equal parts of boric acid, starch, and zinc oxide, are speedily effective. In the school and nursery those responsible for the care of children must be informed of the contagiousness of this unpleasant affection, and measures be instituted accordingly.
3. FUNGOUS SKIN DISEASES
MYCETOMA
Definition.— A fungous disease of warm climates, affecting principally the foot, occasionally the hand, rarely the internal organs or other parts of the body. It is characterized by enlargement and deformity of the part; an oily degeneration and general fusion of the affected tissues; the formation of cyst-like cavities communicating by sinuses, and containing mycotic aggregations in an oily purulent fluid which escapes from fistulous openings on the surface. The disease runs a slow course, is never recovered from spontaneously, and, unless removed, terminates after many years in death from exhaustion.
History and geographical distribution.—The earliest notice of this disease we owe to Keempfer (1712). Its more modern history commenced with Godfrey of Madras, who, in the Lancet of June 10th, 1843, gave a description of several unquestionable examples under the title, " Tubercular Disease of the Foot." Subsequently, Balingall (1855), who was the first to suggest its parasitic nature, Eyre (1860), and others added considerably to our knowledge of the subject. The merit of bringing the disease prominently before the profession, and of distinctly describing its clinical and anatomical features, as well as of suggesting its true pathology, belongs entirely to Vandyke Carter, who, from 1860 to 1874, in a series of important papers, furnished the information on which all later descriptions have been principally founded. Carter was the first to point out the presence of mycotic elements in the discharges coming from the implicated structures, and in the contents of the characteristic cysts and sinuses with which they are honeycombed, and showed that the disease was allied to actinomycosis. Recently much information has been supplied by Wright, Nicolle, Laveran, Bouffard, and, especially, by Brumpt.
In India mycetoma is endemic in districts more or less limited. These districts are scattered over a wide area, the intervening regions— in some instances whole provinces, as that of Lower Bengal— enjoying an almost complete immunity. It appears to be acquired only in rural districts, the inhabitants of the towns being exempt. Among the more afflicted districts may be mentioned Madura— hence the name "Madura foot" by which mycetoma is often known— Hirsar, Ajmeer, Delhi, various places in the Punjab, Kashmir, and Rajputana. In recent years we have accounts of its occurrence with some degree of frequency in Senegambia, Somaliland, Algeria, Egypt, the Soudan, Cochin China, Italy, the United States, and South America. It is probable that in time mycetoma will be found to be endemic in many warm countries in which it has hitherto escaped recognition.
Symptoms.— Mycetoma begins usually, though by no means invariably, on the sole of the foot. The first indication of disease is the slow formation of a small, firm, rounded, somewhat hemispherical, slightly discoloured, painless swelling, perhaps about ½ in. in diameter (Fig. 205). After a month or more this swelling may soften and rupture, discharging a peculiar viscid, syrupy, oily, slightly purulent, sometimes blood-streaked fluid containing in suspension certain minute, rounded, greyish or yellowish particles, often compared to grains of fishroe. In other examples of the disease the particles in the discharge are black, having the size and appearance of grains of coarse gunpowder. Sometimes these particles are aggregated into larger masses up to the size of a pea. In time additional swellings, some of which break down and form similar sinuses, appear in the neighbourhood of the first or elsewhere about the foot. For the most part the sinuses are
permanent, healing up in a very few instances only. Gradually the bulk of the foot increases to perhaps two or three times the normal volume (Fig. 206). There is comparatively little lengthening of the foot; but there is a general increase in thickness, so that in time the mass comes to assume an ovoid form, the sole of the member becoming convex, the sides rounded, and the anatomical points obliterated. The toes may be forced apart, bent upwards at the tarso-phalangeal joints, or otherwise misdirected; so that on the foot being placed on the ground the toes do not touch it. The surface of the skin is roughened by a number of larger or smaller, firmer or softer hemispherical elevations, in some of which the orifices of the numerous sinuses open. Most of these orifices are easily 
Fig. 205.—Mycetoma of about two years' standing. (After Legrain.)
Fig. 206.—Section of a Madura foot. (T. R. Lewis.)
The discharge issuing from the sinuses differs in amount in different cases, and from time to time in the same case; whether profuse or scanty, it always exhibits the same oily, mucoid, slightly purulent appearance, and may stink abominably. With a very few exceptions it contains either the grey or the black grains already referred to; rarely similar bodies of a reddish or pink colour.
To the touch the swollen foot feels somewhat elastic, and does not readily pit on pressure. The sensibility of the skin is preserved. Although complained of in some instances, severe pain is rarely a prominent feature. The principal complaint is of inconvenience from the bulk and weight of the mass, and, in advanced cases, of the uselessness of the limb for locomotion. In time the foot is no longer put to the ground, different unnatural styles of progression being adopted by different patients.
As the foot enlarges the leg atrophies from disuse; so that in the advanced disease an enormously enlarged and misshapen foot, flexed or extended, is attached to an attenuated leg consisting of little more than skin and bone. In some the tibia, or, if the hand is the seat of invasion, the bones of the forearm become involved; in others the disease at first may be confined to a toe, or a finger, or other limited area. In a very few instances the seat of the disease is the knee, thigh, jaw, or neck. Unless the case be one of actinomycosis the internal organs are never specifically implicated, either primarily or secondarily. The lymphatic glands likewise, although they may be the subject of adenitis from secondary septic infection, are very rarely involved.
After ten or twenty years the patient dies, worn out by the continued drain, or carried off more suddenly by diarrhoea or other intercurrent disease.
Classification, etiology, and histology.— Formerly the tropical forms of mycetoma were classified according to the colour of the mycotic particles in the discharge. Thus we had the white or ochroid, the black or melanoid, and the red forms of mycetoma, the last being a very rare variety. Brumpt's investigations have made possible a classification more scientific than this crude clinical one; the latter, therefore, has to be abandoned.
This authority distinguishes eight different kinds of mycetoma, two of which are caused by species of Discomyces. Of the other six, two are certainly caused by species of Aspergillus. The remaining four are also probably due to species of aspergillus, but, in the absence of cultural evidence, he places them in two provisional groups: one of these, embracing the unpigmented septate species, he names Indiella; the other, the pigmented species, he calls Madurella. Moreover, he has shown that the fungi which give rise to mycetoma may present not only resisting forms such as sclerotia and chlamydospores, but also characteristic spore apparatus (Aspergillus nidulans, A. bouffardi). The species are as follows:—
i. ACTINOMYCOTIC MYCETOMA
Caused by the ray -fungus, Discom^ces bovis (Harz, 1877). Actinomycosis has a world-wide distribution and is a common disease of cattle. It occurs also in hogs. In men it may attack the extremities, giving rise to a tumour clinically indistinguishable from other kinds of mycetoma, or it may develop in the jaw, the tongue, lungs, liver, brain; and occasionally the primary lesion may be followed by metastases in all parts of the body.
The fungus of actinomycosis develops equally well in most tissues. It destroys bone by erosion and spares only nerves and tendons. The pus from the affected region contains small yellowish granules ("sulphur grains") of irregular shape, attaining at most 0'75 mm. in diameter. They are soft and consist of an inextricable felted mass of inycelia. The threads are radially arranged at the periphery of the grain, and their free extremity widens into a bulbous, club-like termination (10-20 μ. long by 8-10 μ wide). These clubbed ends have been looked upon by several authors as forms of degeneration. Brumpt points out that they consist of young, active protoplasm, and holds that they are functionally hypertrophied while elaborating food for the colony. In old grains the clubs disappear, their protoplasm being utilized in the formation of spores.
This fungus gives rise to ramified sinuses which extend in all directions, opening at the surface by numerous vents. The sinuses are surrounded by a thick fibrous sheath of connective tissue. The centre of the largest tunnels is softened, the youngest grains being at the periphery surrounded by polynuclear cells and almost in contact with the sclerosed tissues which separate the cavities and sinuses.
The parasite has been successfully cultivated, and the disease has been inoculated both with the natural and the artificially grown organism.
Discomyces bovis lives saprophytically on certain plants. It has been found on the spikelets of cereals ('Hordeum murmium L., Phleum pratense L., etc.), and is therefore probably inoculated through the skin or mucous membranes in the same way as the fungi which give rise to other kinds of mycetoma.
The diagnosis of the disease from tertiary syphilis and bone tuberculosis rests on the characteristic grains present in the pus.
The disease is progressive and of grave import. The treatment is largely surgical. In early cases iodide of potassium in doses of from 40 to 60 grains daily has proved advantageous, and in some cases even curative. ii. VINCENT'S WHITE MYCETOMA
Caused by Discomyces maduræ (Vincent, 1894). This kind of mycetoma is common and widely distributed. It has been observed in Algeria, in Abyssinia, in Somaliland, in the island of Cyprus, in India, in the Argentine Republic, and in Cuba.
It runs a slow course. Unlike D. bovis and other mycetoma-producing fungi, it does not destroy bone, and does not seem to act directly on the general health of the patient, though ultimately and indirectly it may bring about cachexia.
The grains formed by Discomyces maduræ vary in size from that of a pin's head to that of a pea. They are of a yellowish-white colour, present a mulberry-like surface, are soft and easily crushed. Their mode of growth is absolutely characteristic. The grain throws out from its periphery radiating filaments. Between these fungus threads are numerous lymphocytes (likewise arranged in radial series) embedded in an amorphous substance, probably arising from the destruction of lymphocytes, epithelial cells, and macrophages, on which the mycelium feeds. The crown of amorphous rays round the grain is typical. The grain is surrounded by numerous polynuclear leucocytes. Having attained from 1 to 1.5 mm. diameter, the grain projects small shoots which become detached from the parent grain, enlarge, and reproduce the characteristic radial structure. Other grains form also, and, after a time, the typical large mulberry granule is formed, the central grains degenerating. The grains are found in cavities surrounded by inflammatory connective tissue permeated by polynuclear cells and occasionally giant cells.
iii. NICOLLE'S WHITE MYCETOMA
Caused by Aspergillus nidulans (Eidam, 1883). So far only one case has been observed, in Tunis, but probably it occurs in many places, the parasite Aspergillus nidulans being widely distributed. The grains formed by this fungus may also attain the size of a pea, but they differ from those of Discomyces madurœ, inasmuch as they are more or less spherical and present a smooth surface.
In this form of mycetoma the bones are attacked and destroyed.
iv. BOUFFARD'S BLACK MYCETOMA
Caused by Aspergillus bouffardi (Brumpt, 1906). This form was discovered by Bouffard at Djibouti, Somaliland. Lewis seems to have met a similar case in India; a third case, probably also belonging to this species, was described by Bovo in Italy.
The grains are quite characteristic. They are black in colour and vary in size from a pin's head to that of No. 1 shot. They present a mulberry-like surface which is smooth and glossy. They are somewhat elastic, but break when pressed. Their structure is remarkable. It consists of a coiled-up mass. Maceration in water for about twenty-four hours causes the grain to unfold. Sections show that the grain is composed of a densely felted mycelium of a silvery-white colour, with a peripheral zone of irregularly moniliform threads with terminal chlamydospores cemented together by a dark brown interstitial substance.
The grains are found in the cellular tissue, always singly and within small cavities. Each grain is surrounded by enormous giant cells, and by epithelioid cells of all sizes, and is enclosed in a characteristic shell of connective tissue.
This kind of mycetoma appears to be more amenable to treatment. Bouffard's and Bovo's cases were radically cured by curettage. In Bovo's case a secondary extension to the groin lymphatics of tbe affected side had suggested the diagnosis of melano-sarcoma.
v. CLASSIC BLACK MYCETOMA
Caused by Madurella mycetomi (Laveran, 1902). This mycetoma has a very wide distribution. It has been observed in Italy, in Africa (Senegal, French Soudan), and in India.
The grain formed by Madurella, mycetomi is dark brown or black in colour. It measures 1 to 2 mm. in diameter, is hard and brittle; its surface is irregular and frequently presents pointed eminences which differentiate it from the larger and smooth grains of Aspergillus bouffardi. The grain is composed of white threads, always over 1 μ in diameter and attaining at times 8 to 10 μ., which secrete a dark brown substance that cements them together. The grain is first surrounded by giant cells, epithelioid cells, and numerous polynuclear cells, and shows numerous chlamydospores at the periphery. Then a thick capsule of fibrous connective tissue forms round it. This puts an end to the vegetation of the fungus, which passes into a resting stage and is converted into sclerotia, in which form it is eliminated. This was shown by Carter as early as 1860. The grains form rapidly within the tissues. Brumpt reports a case in which they were eliminated in large numbers one month after the commencement of the disease.
Each grain may become the centre of an active colony, which continues to 'extend, destroying the surrounding tissues, until arrested by a barrier of sclerosed tissue. Thus large tumours may be formed. In very old grains the mycelium presents cavities filled with numerous chlamydospores. Sometimes, on account of unfavourable conditions, certain lobes of the fungus separate from the rest of the colony and become independent grains. This mode of vegetation, characteristic of the species, gives to the lesions a typical rosette-like appearance.
vi. BRUMPT'S WHITE MYCETOMA
Caused by Indiella mansoni (Brumpt, 1906). This form was described from a specimen of Indian origin in the museum of the London School of Tropical Medicine.
The grains peculiar to this form are hard, white, and very small, varying in size between ⅛ and ¼ mm., and having a lenticular shape. Some are bean-shaped and flat. To study their structure it is necessary to boil them first in a solution of caustic potash. The hyphal threads are large and closely set, but without any cementing substance between them. The periphery of the grain contains numerous large chlamydospores with thick wall and full of protoplasm.
The grains of Indiella mansoni are always numerous within the inflammatory tissue. The latter is brownish and is not surrounded by a well-marked sheath of connective tissue as in other mycetomas. It contains numerous polynuclear cells, a few lymphocytes, and some macrophages.
vii. REYNIER'S WHITE MYCETOMA
Caused by Indiella reynieri, Brumpt, 1906. This form was found in Paris by Keynier.
The grains may attain 1 mm. in diameter; they are soft, white, and consist of a coiled-up strand, which gives them a peculiar appearance resembling the excrement of earthworms. They are made up of a dense felting of hyphal threads, the peripheral branches of which usually terminate in chlamydospores divided into two or three compartments. The hyphæ are bound by a scanty cement, which is easily dissolved out by boiling in caustic potash.
viii BOUFFARD'S WHITE MYCETOMA
Caused by Indiella somaliensis, Brumpt, 1906. This form is perhaps even more common in India than Vincent's white mycetoma. Bouffard has found it twice in Somaliland.
{{smaller|Indiella somaliensis is a most destructive fungus. In a foot examined by Brumpt all the muscles, tendons, and bones had been replaced by sclerosed tissues more or less homogeneous and presenting numerous sinuses full of yellowish grains clustered together like fish-roe, and many small inflammatory nodules containing one or more grains.
The grains vary in colour from white to reddish yellow; they are small, smooth, and attain on an average about 1 mm. in diameter. They are spherical when single, but polyhedral from reciprocal pressure when clustered in masses. The parasite in its earliest stage is always found in a giant cell, showing as an irregular mass which stains more deeply than the enclosing cell. Usually several infected cells coalesce; the grain which results is surrounded by an amorphous layer produced by the destruction of the elements which form its substratum. The grains are not enclosed within nodules, as is the rule in certain mycetomas, but spread exactly like those of actinomycosis.
In the amorphous zone of cellular detritus Brumpt found a discomyces which seems to live symbiotically with Indiella somaliensis. In attempts at culture BoufFard found that this discomyces was the only organism that grew. Other investigators— Boyce, Vincent, Musgrave and Clegg, etc.— have cultivated a streptothrix from the white variety, differing from the actinomyces in producing no pigment and forming white raised colonies on agar. Probably there are several conditions in actinomycosis, as in mycetoma, bearing a general resemblance to each other, but differing slightly according as they are produced by different species of streptothrix.
Morbid anatomy.— On cutting into a mycetomatous foot or hand the knife passes readily through the mass, exposing a section with an oily, greasy surface, in which the anatomical elements in many places are unrecognizable, being, as it were, fused together, forming a pale, greyish-yellow mass. The bones in parts have entirely disappeared; where their remains can still be made out the cancellated structure is very friable, thinned, opened out, and infiltrated with oleaginous material. Of all the structures the tendons and fasciæ seem to be the most resistant.
The most remarkable feature revealed by section is a network of sinuses and communicating cyst-like cavities of various dimensions, from a mere speck to a cavity an inch or more in diameter. Sinuses and cysts are occupied by a material unlike anything else in human morbid anatomy. In the black varieties of mycetoma this material consists of a black or dark brown, firm, friable substance which, in many places, stuffs the sinuses and cysts; manifestly it is from this that the black particles in the discharge are derived. In the white varieties the sinuses and cysts are also more or less stuffed with a white or yellowish roe-like substance, evidently an aggregation of particles identical with those escaping in the corresponding discharge. The black substance, which can be readily turned out, is moulded into truffle-like masses ranging in size from a mere grain to a small apple, according to the capacity of the cysts or sinuses containing it. The roe-like particles in the white varieties are held together by a softer, cheesy -looking material. The sinuses and cysts occupy the bones, muscles, or fasciae indiscriminately; they are found principally in the fat and the connective tissue. They are lined with a smooth membrane, adherent when in the soft tissues, but capable of being enucleated when in the bones. Some of the cysts do not communicate with sinuses; most of them, however, do so, and with each other, opening on the surface of the skin at the mammillated fistulæ already referred to. In the very rare red variety the colour of the accretions is red or pink.
Under the microscope the mycotic elements can be readily recognized in the concretions. In microscopic sections of the tissues evidences of extensive degenerative changes, the result of a chronic inflammatory process, can be made out. An important feature as bearing on the pathology of the disease, and one which was long ago described by Lewis and Cunningham, has been insisted on more recently by Cunningham, namely, a sort of arteritis obliterans or extensive proliferation of the endothelium of the arteries and, according to Vincent, a thickening of the adventitia of the vessels as well as of the capillaries in the more affected areas.
Mode of entrance of the fungus.— Little is known on this point. It is conjectured that the fungi live as parasites on certain plants, and that they may penetrate the tissues of man through a wound in the skin. The peculiar endemicity and geographical distribution of the disease, and the facts of its occurring almost invariably on the feet or hands, and principally in bare-footed agriculturists, favour this view.
Treatment.— The only effective treatment, in the case of implication of a considerable part of the foot or hand, is amputation. This must be performed well above the seat of the disease; for it must be borne in mind that the long bones may be implicated as well as the small bones, and that unless- the entire disease be removed it will recur in the stump. Complete removal is not followed by relapse. If a toe, or a small portion of the foot or hand, is alone involved, this may be excised with success. Potassium iodide has been found to be beneficial in certain forms.
BLASTOMYCOSIS
This term is used to indicate lesions, other than mycetoma, produced by the proliferation of certain yeast-like fungi in the tissues. Normally these fungi are either saprophytic or live as parasites on animals and plants. They appear to be especially abundant in tropical countries. Doubtless they get access to the tissues through some wound or breach of surface. A number of species, distinguishable perhaps by the mycologists, have been described; for the clinician it suffices to know that in the morbid discharges and tissues they occur and are recognizable as yeast-like cells. In some instances the parasites are limited to one particular spot; in others they are more diffuse, and may attack almost any organ or tissue. The following clinical types have been recognized:—
1. The cutaneous.— Patches of various dimensions of small warty excrescences with minute abscesses or encrusted ulcers, especially at the periphery of the patch.
2. Oral.— Lesions resembling the foregoing, which develop in or spread to the mucosa of the mouth and throat, and eventuate in deep ulceration and perhaps fatal destruction of the part.
3. Coccidial.— The skin lesions are similar to type -1, but usually larger and coarser. The viscera becoming involved, death ensues. In the affected tissues peculiar round bodies, 3 to 80 μ in diameter, many of them containing a multitude of spores, are a feature.
4. Gluteal.— There is extensive brawny thickening of one or both gluteal regions, the superjacent skin being thickened and coarse and perforated with the openings of many communicating sinuses. The condition is apt to be regarded as an aggravated form of fistula in ano.
5. Sporotrichosis.— Gumma-like swellings in limbs or trunk, which enlarge and ultimately break down, leaving deep ulcers. The lymphatics, oral cavity, periosteum, muscles, or viscera may become involved. In the discharges and tissues the parasites are scanty, so that the niycotic nature of the disease can be made out only from cultures in glucose-agar tubes.
Diagnosis.— Usually these lesions in the first instance suggest syphilis or tuberculosis. Specific treatment and absence of reaction to tuberculin and of the bacillus of tubercle should lead to a careful search for yeast-like organisms in the discharges or scrapings.
Treatment.— All forms of blastomycosis are exceedingly chronic and resistant to treatment. Surgical measures are useless, but large doses of the iodide of potassium or of sodium (2030 gr. three times a day, well diluted) are sometimes effective, and should always be tried, and continued, if found beneficial, until cure is well established. The X-rays are at times a useful adjunct.
DHOBIE'S ITCH
In view of the recent researches of Sabouraud and others on the ringworms of Europe, there can be little doubt that the ringworms of warm countries are attributable to a large variety of fungus forms, probably many of them derived from the lower animals. Although, in a general way, we are familiar enough with the clinical features of these ringworms, their specific germs have not as yet been very closely studied. By the lay public all epiphytic skin diseases, more especially all forms of intertrigo, are spoken of as dhobie's (washer- man's) itch, in the belief, probably not very well founded, that they are contracted from clothes which have been contaminated by the washerman. There are many sources of ringworm infection in warm climates besides the much-maligned dhobie.
In the tropics, native children often exhibit dry, scurfy patches of ringworm on the scalp; and the skin of the trunk and limbs of adults is not infrequently affected with red, slightly raised, itching rings, or segments of rings, of trichophyton infection. Sometimes these rings enclose areas many inches in diameter.
Pityriasis versicolor is also very common in the tropics. It is the usual cause of the pale, fawn-coloured, slightly scurfy patches so frequently a feature on the dark-skinned bodies of natives. On the dark-pigmented skins of negroes, Indians, and dark-complexioned Chinese the patch of pityriasis—contrary to what obtains in Europeans and light-skinned Chinese— is usually paler than the healthy integument surrounding it. The pigment in the fungus and the profuse growth of the latter conceal, as a coat of paint might, the dark underlying natural pigment of the skin, which, moreover, in certain cases seems to be affected (either increased or decreased) by the action of the fungus. Castellani has recently studied the several forms of mycotic pityriasis as they occur in Ceylon. He recognizes three forms: Pityriasis versicolor flava, produced by Microsporon tropicum, a fungus having a thick, irregular, constricted mycelium; Pityriasis versicolor alba, produced by a very minute fungus with straight, short mycelia, Microsporon macfadyeni; and Pityriasis versicolor nigra— a variety I had described many years ago as occurring in South China— produced by Microsporon mansoni, which contains much dark pigment in the mycelial tubes, and which on culture in maltose-agar produces black hemispherical colonies.
The expression dhobie's itch, although applied to any itching, ringworm-like affection of any part of the skin, most commonly refers to some form of epiphytic disease of the crutch or axilla. There are at least three species of vegetable or bacterial parasites which in the tropics are prone to attack these situations—namely, the trichophytons or ordinary body ring-worms, the Microsporon minutissimum of erythrasma, and the germ of the disease I have described under the name pemphigus contagiosus.
The suffering to which some of the forms of dhobie's itch give rise is often severe. In hot, damp weather especially, the germs proliferate actively, producing, it may be, smart dermatitis. The excessive irritation thus set up leads to scratching and, very likely, from secondary bacterial invasion, to boils or small abscesses. The crutch, or axillæ, or both, are sometimes rendered so raw and tender that the patient may be unable to walk or even to dress. The irritation and itching are usually worse at night, and may keep the patient awake for hours. Even in the absence of treatment, when the cold season comes round the dermatitis and irritation subside spontaneously. The affected parts then become dry, pigmented, and scurfy, and the fungus remains quiescent until the return of the next hot weather.
Diagnosis.— The diagnosis of mycotic dermatitis is usually easily made. The festooned margin is almost conclusive. In the case of pemphigus contagiosus the characteristic blebs, the smooth, raw, or glazed surfaces, and undermined epidermic rings are usually very apparent and render diagnosis easy. When doubt exists, recourse to the microscope may be necessary; but, owing to the inflamed condition of the parts, there may be much difficulty in finding fungus elements even when the case is certainly epiphytic. A negative result is, therefore, not always conclusive against ringworm.
I am convinced that many cases of dhobie's itch are produced by Microsporon minutissimum, and that they are really inflamed erythrasma and not trichophyton ringworm. During cold weather one often sees, on the site of what, during the summer, had been a troublesome dhobie's itch, a brownish furfuraceous discoloration of the crutch or axilla. The same appearance I have remarked in Europe in Europeans who had suffered from dhobie's itch in the East, and on examining scrapings from the parts have found M. minutissimum in abundance. It would seem, therefore, that during the heat and moisture of a tropical summer this generally very unirritating parasite becomes more active and excites dermatitis. The same may sometimes be seen in pityriasis versicolor. I believe that those cases of Microsporon— furfurand minutissimum— dhobie's itch are more easily cured than the trichophyton varieties.
Treatment. After a thorough use of soap and water, the application of Vlemingkx's solution of sulphuret of calcium (1 oz. quicklime, 2 oz. precipitated sulphur, 15 oz. water, boiled together in an earthenware vessel till reduced to 1 oz.; decant the clear sherry-coloured fluid after subsidence) every night for three or four times generally brings about a rapid cure. If the parts are inflamed and tender the solution should be diluted to half or one-quarter strength for the first two applications. A preliminary soothing treatment by lead lotion, or an ichthyol or hazeline ointment is desirable in such cases. A tincture of the leaves of Cassia alata painted on, or vigorous rubbing with the crushed leaves themselves, is equally successful. If these fail, chrysophanic acid ointment, 20 gr. to the ounce of vaseline, rubbed in twice a day till a slight erythema shows at the edge of the diseased patch, is almost invariably successful. When prescribing chrysophanic acid the physician must be careful to inform the patient of its staining effect on clothes; to warn him to stop its use so soon as the erythematous ring shows; and to be careful not to apply the ointment to the face. A writer in the Indian Med. Gaz. (Jan., 1898) strongly recommends the application of glacial acetic acid. It cures, he affirms, with, at most, two applications. The smarting its use entails is relieved by laying a lump of ice in a handkerchief on the part. Castellani and Chalmers recommend an ointment of resorcin ʒi, salicylic acid gr. x, lanolin, vaseline, āā ʒiv, to be applied twice a day. For the ringworms of the thick-skinned natives linimentum iodi freely applied, and of double strength, is the best and a most efficient remedy.
Prophylaxis.—The various forms of crutch dhobie's itch may be avoided by wearing next the skin short cotton bathing-drawers and changing them daily; at the same time powdering, after the daily bath, the axillæ and crutch with equal parts of boric acid, oxide of zinc, and starch.
Tinea imbricata (Plate XV.)
Definition.—A form of body ringworm, until lately peculiar to certain Eastern oceanic tropical climates, produced by a trichophyton, and characterized by a concentric arrangement of closely set rings of scaling epidermis.
Geographical distribution.—This peculiar form of epiphytic disease is strictly confined to warm climates. It is principally met with in the Eastern Archipelago and in the islands of the South Pacific, although it has been found to extend westward as far as Burma, and northward as far as Foochow and Formosa on the coast of China. In many of the islands of the South Pacific it affects a large proportion of the inhabitants; in some islands quite one-half. There is good reason to believe that its area of distribution is gradually extending. Thus Turner and Koniger tell us that it was formerly unknown in Samoa and Bowditch Islands, where it is now very prevalent. Daniels informs me that it was introduced for the first time into Fiji by some Solomon Islanders in 1870; by 1872 it had become general among the Fijians. It was recently introduced into Tahiti, and rapidly spread there among the natives. We now hear of it in tropical Africa. Recently it has been described by Paranhos and Leme as occurring in the interior of Brazil. Once introduced, it spreads very rapidly in countries with a damp, equable climate and a temperature of 80° to 90° F. Very high or very low temperatures and a dry atmosphere are inimical to its extension.
Symptoms.—Tinea imbricata is easily recognized. At first it may be confined to one or two spots on the surface of the body; usually, in a short time, it comes to occupy a very large area. It does not generally affect the soles and palms, although it may do so; nor is the scalp a favourite site. Baker, confirmed by Tribondeau, remarks that it avoids the crutch, the axillæ, and, contrary to Castellani's experience, the nails. With these exceptions it may, and commonly does, sweep over and keep its hold on nearly the entire surface of the body; so that after a year or two a large part of the skin is covered with the dry, tissue-paper-like scales, arranged in more or less confused systems of concentric parallel lines, absolutely characteristic of the disease.
An inoculation experiment readily explains the production of the scales, their concentric parallel arrangement, and the mode of extension of the patches. About ten days after the successful inoculation of a healthy skin with tinea imbricata, the epidermis at the seat of inoculation is seen to be very slightly 
Tinea imbricata.
Plate XV.
The scales, if not broken by rubbing, may attain considerable length and breadth; but, of course, their dimensions are in a measure determined by the amount of friction they are subjected to. Usually they are largest between the shoulders— that is, where the patient has a difficulty in scratching himself. The lines of scales are from ⅛–½ in. apart. The hair of the scalp is not injured.
The fundus.— On detaching a scale and placing it under the microscope, after moistening with liquor potassæ, a trichophy ton-like fungus can be seen in enormous profusion. The parasite evidently lies between epidermis and rete, and by its abundance causes the. former to peel up. As the fungus does not die out in the skin travelled over, it burrows under the young epithelium almost as soon as the latter is reproduced. Hence the peculiar concentric scaling and the persistency of the disease throughout the area involved. When the scales are washed off by the vigorous use of soft soap and hot water, the surface of the skin is seen to be covered with parallel lines of a brownish colour— evidently the slightly pigmented fungus proliferating and advancing under the young epidermis. Tribondeau, on the evidence of finding fructification in one of his attempts at culture, pronounces the fungus to be a lepidophyton and not a trichophyton. Castellani has succeeded in cultivating the true parasite; this he has proved by the reproduction of the characteristic skin lesions by inoculation of his cultures. He considers that in tinea imbricata we have to deal with at least two distinct species, which he has named Endermophyton concentricum and E. indicum. Castellani obtained cultures by immersing imbricata scales in alcohol for five to ten minutes and then placing them in tubes of glucose broth— one scale in each tube. Usually most of the tubes become contaminated with bacteria, but a few remain clear; in the latter, in five to ten days, fine white threads may be seen spreading from the scales. In three to four weeks, if portions of this are transferred to solid agar media, characteristic cultures can be obtained, and are inoculable into the human subject.
Diagnosis.— From ordinary ringworm tinea imbricata is easily distinguished by the absence of marked inflammation or congestion of the rings, by the abundance of the fungus, by the large size of the scales, by the concentric arrangement of the many rings or systems of rings, by the non-implication of the hair, and, according to Baker, by the avoidance of crutch and axillæ. From ichthyosis it is distinguished by the concentric arrangement of the scaling, by the peripheral attachment of the scales, and by the presence of abundant fungus elements.
Treatment.— The best treatment for tinea imbricata in natives is the free application of strong linimentum iodi. Limited patches might be treated with chrysophanic acid ointment (20 gr. to the ounce) or by rubbing with the bruised leaves of Cassia alata. Paranhos and Leme recommend a tepid alkaline bath of sodium bicarbonate (1 kilogramme to 20 litres of water), followed by the application of ocalia perdiceps 50 grm., glacial acetic acid 15 grm., macerated for two days in glycerinated water (10 per cent.) 985 grm., and then filtered. Sulphur ointment, or sulphur fumes, act very slowly and unsatisfactorily. Clothes should be boiled or burned.
Prophylaxis. Daniels informs me that tinea imbricate is a comparatively rare disease in Tonga. This circumstance the natives attribute to their custom of oiling the body. Daniels remarks that of late years, since the Fijians adopted the same practice, the disease has become somewhat less prevalent among them. Personal cleanliness, and the immediate and active treatment of any scaling spot, should be carefully practised in the endemic countries.
In Tahiti the use of chrysophanic acid is now general among the natives; as a consequence the disease is not so prevalent there as it was only a few years ago.
PINTA
Definition.— An epiphytic disease characterized by peculiar pigmented patches on the skin.
Geographical distribution.— In certain districts in tropical America, especially along the river banks in Mexico, Central America, Venezuela, Colombia, Bolivia, and one or two places in Peru, Chile, and Brazil— the district between the Juciparana and the Santo Antonio rivers (Magalhães, private letter)— there occurs an epiphytic skin disease characterized by peculiar red, or blue, or black, or white piebald spotting of the skin of a part, or of the whole, of the body. The patient emits an offensive odour, sometimes compared to that of a mangy dog or of dirty linen. Desquamation and itching of the patches are also features of the disease. It entails no constitutional disturbance and no danger to life. Like other epiphytic diseases, want of personal cleanliness has a great deal to do with the prevalence of pinta in the districts mentioned, for it is rare in cleanly whites or well-to-do negroes; the dirty Indians and the poor half-castes are those most frequently affected. In some districts it occurs in nearly a tenth part of the inhabitants, in others nearly the entire population is affected. Lately a somewhat similar disease has been seen in North Africa,*[1] in Egypt, and possibly in the Malay Peninsula.
Symptoms.— Pinta commences at one or two points, the rest of the surface of the skin becoming infected in turn by extension or by auto-contagion. At first the hands, or face, or some other exposed parts, are attacked. The original patch may be white, red, blue, or black. It gradually increases in size, becoming scurfy and itchy, particularly when the surface is warm. As the patches spread they assume a variety of shapes. Fresh spots appear in the neighbourhood of the parent spots, into which, in course of time, they tend to merge ; so that ultimately large patches of discoloured skin are formed. The palms of the hands and the soles of the feet are not attacked. On the scalp becoming affected the hair turns white and thin, and ultimately falls out. When fully developed, the disease produces a very grotesque appearance. It is probable that the white patches in a proportion of cases are not epiphytic, as they neither itch nor desquamate; very likely they are ordinary leucodermia, possibly brought about through disturbance of the natural pigmentation by a parasite which had subsequently died out. Sensation and the glandular functions of the skin are not affected. In consequence of the scratching, the implicated parts may become cracked or ulcerated.
Two types of the disease have been named the superficial epidermic and the deep epidermic; the former being represented by black and blue patches which spread rapidly; the latter including the red and white patches, apparently involving the rete and deeper layers of the epidermis, spreading more slowly, and, at the same time, being more difficult to cure. The various forms and colours may concur in the same individual; but a given patch, once established, does not change colour.
Pinta is contagious. It attacks both sexes and any age. Unless properly treated it may last for years.
Pathology.— If one of the scales is moistened with liquor potassæ and placed under the microscope, black spores and a white, highly refracting mycelium are found. The spores are round or oval, measuring 8 μ to 12 μ in diameter. Abundant pigment is seen floating in a yellowish fluid in the interior of the spore. The mycelial filaments are short, non-branching, tapering from a broad base to a blunt point by which each filament is attached to a single spore, like the stalk to a cherry. The mycelium measures from 18 μ to 20 μ in length by 2 μ in breadth. The differences in the colour of the patches probably depend on differences in the pigmentation, or kind, of the fungus. Such is Gastambide's description of the parasite— a description which, to some extent, is borne out by Osborne Browne.
Montoya y Florez has published an elaborate and careful description of the disease and of the various mycotic growths he found in the several varieties of pinta which he studied. He says that he has never seen a fungus answering to Gastambide's description. On placing the scales moistened with liquor potassæ under the microscope, long dichotomous filaments, generally very fine and cylindrical, in certain conditions granular and beaded, are seen. In places this mycelium forms a dense network. Here and there veritable ropes of mycelium are visible, or broad, short filaments with fructification characteristic of the particular variety of the disease may be detected (Fig. 207), He has succeeded in cultivating the various fungi, which apparently belong to a plurality of genera— Penicillium, Aspergillus, Manilla.
Diagnosis.— This disease is readily diagnosed 
Fig. 207.—Fructification of cryptogamic epiphytes in pinta. (After Montoya y Florez.)
a, Red pinta; b, dark violet pinta; c, grey-violet pinta; d, blue pinta.
Treatment.— Chrysophanic acid, preparations of sulphur, strong liniment of iodine, and other epiphyticides are indicated. Cleanliness and the destruction of old clothes are indispensable.
PIEDRA
This peculiar disease of the hair is very common in certain districts of Colombia, South America. So far as is known, it is confined to the inhabitants of that country, of whom a considerable proportion, both male and female, and apparently belonging to all the races represented there, are affected.
According to Juhel-Rénoy, whose observations practically coincide with the earlier accounts by Desenne, Cheadle, Morris, and others, the hairs of the affected scalp are dotted over at irregular intervals with numerous— twenty-three in a hair 60 cm. in length— minute, gritty nodosities. These, barely visible to the naked eye, are distinctly perceptible to the touch when the hair is drawn between finger and thumb. The affected hairs are bent and twisted, and tend to produce matting and knotting. The little nodosities, which, though very firm, are not so hard as the name piedra (a stone) would indicate, being easily cut through with a sharp knife or scissors, are paler than the hair which they surround, or partly surround, like a sheath. When a comb is drawn through the hair a sort of crepitation is produced, doubtless by the friction against the hard particles.
Under the microscope these excrescences are found to consist of a number of spore-like bodies, easily made apparent by soaking the hair in liquor potassæ after washing in ether. The spores (which are twice the size of trichophyton spores and remarkably refringent) from mutual pressure are polyhedral, and together form a sort of tessellated mosaic, the elements of which seem to be held together by a greenish soluble cement in which a number of minute bacteria-like rods are incorporated. The shaft of the hair—not eroded or affected in any way—can be seen intact through the encrusting fungus.
Piedra is supposed by some to be induced by the mucilaginous hair applications in vogue among the Colombians. Although Juhel-Rénoy has given to it the name "trichomycose nodulaire," it must not be confounded with the trichomycosis nodosa of Paterson (the leptothrix of Wilson), which is quite a different affection and common enough on the axillary, scrotal, and face hair in Europe and elsewhere. Neither must it be confounded with trichorexis nodosa, a
Fig. 208.—Chigger (Dermatophilus penetrans). (Blanchard.)
non-parasitic disease of the hair-shaft, which is split up at different points into brush-like bundles of fibres and is thus easily fractured; nor with moniliform hair (monilethrix, Crocker), a congenital, hereditary, and also non-parasitic disease.
Treatment.—Cleanliness, the free use of soap, and the application of some epiphyticide should suffice for cure. Should such means fail, doubtless shaving the scalp would be effectual.
4. SKIN DISEASES CAUSED BY ANIMALS
The Chigger, or Sand Flea (Dermatophilus penetrans)
This insect, formerly confined to the tropical parts of America (30° N. to 30° S.) and to the West Indies, appeared on the West Coast of Africa for the first time about the year 1872. Since that date it has spread all over the tropical parts of that continent and even to some of the adjacent islands— Madagascar for example. As a cause of suffering, invaliding, and indirectly of death, it is an insect of some importance. It is now extremely prevalent on the East Coast of Africa, and is causing a large amount of invaliding amongst the Indian coolies there, by whom it has been introduced into India.
The chigger (Fig. 208) is not unlike the common flea (Pulex irritans) both in appearance and, with one exception, in habit. It is somewhat smaller in size—1 mm., the head being proportionately larger and the abdomen deeper than in the latter insect. In colour it is red or reddish brown. Like the
Fig. 209.—Chigger: impregnated female. (Blanchard.)
flea, its favourite haunt is dry, sandy soil, the dust and ashes in badly kept native huts, the stables of cattle, poultry pens, and the like. It greedily attacks all warm-blooded animals, including birds and man. Until impregnated, the female, like the male, is free, feeding intermittently as opportunity offers. So soon as she becomes impregnated she avails herself of the first animal she encounters to burrow diagonally into its skin, where, being well nourished by the blood, she proceeds to ovulation. By the end of this process her abdomen, in consequence of the growth of the eggs it contains, has attained the size of a small pea (Fig. 209). The first anterior and the two posterior segments do not participate in the enlargement, the latter acting as a plug to the little hole made by the animal when she entered the skin. When the ova are mature they are expelled and fall on the ground. In a short time a thirteen-ringed larva is hatched out from each egg. This larva presently encloses itself in a cocoon, from which, in eight or ten days, the perfect insect emerges.
During her gestation the chigger causes a considerable amount of irritation. In consequence of this, pus forms around her distended abdomen, which now raises the inflamed integument into a pea-like elevation. After the eggs are laid (according to some, before this process) the superjacent skin ulcerates and the chigger is expelled, leaving a small sore which, if
Fig. 210.—Chiggers in sole of foot. (From a photograph by Daniels.)
infected by any pathogenic micro-organism, as the bacterium of phagedæna or of tetanus, may lead to grave consequences.
Naturally, being nearest the ground, the feet are the parts most commonly infested by chiggers. The soles of the feet (Fig. 210), the skin between the toes, and that at the roots of the nails are favourite situations. Other parts of the body are by no means exempt; the scrotum, penis, the skin around the anus, the thighs, and even the hands (Fig. 211) and face, are often attacked. Usually only one or two chiggers are found at a time; occasionally they are present in hundreds, the little pits left after their extraction being sometimes so closely set that parts of the surface may look like a honeycomb.
Fig. 211.—Chigger lesions of hands and feet. (From a photograph by Daniels.)
Treatment.—In chigger regions, houses, particularly the ground floors, must be frequently swept and accumulation of dust and débris be prevented. The housing of cattle, pigs, and poultry must be similarly attended to. The floors should be sprinkled often with carbolic water, pyrethrum powder, or similar insecticide, and walking barefooted must be avoided. Bathing must be practised daily, and any chiggers that may have fastened themselves on the skin at once removed. They may be killed by pricking them with a needle, or by the application of chloroform, turpentine, mercurial ointment, or similar means, after which they are expelled by ulceration. The best treatment, however, is not to wait for ulceration,
Fig. 212.—Chrysomyia macellaria, female.
but to enlarge the orifice of entrance with a sharp, clean needle and neatly to enucleate the insect entire. Some native women, from long practice, are experts at this little operation. The part must be
Fig. 213.—Chrysomyia macellaria, larva.
dressed antiseptically and protected until healed. Europeans living in an endemic district should wear high boots. A daily inspection of the feet, especially under the nails, is advisable. Should any black dot be discovered, the chigger should be removed at once.
Myiasis
The Screwworm (Chrysomyia macellaria)
This is the larva of a dipterous insect (Fig. 212) common in certain parts (especially the tropics) of America, from Canada to Patagonia. The insect (9-10 mm. long) lays a mass
Fig. 214.—Native with Chrysomyia macellaria in nostrils and frontal sinuses; early stage. (From a photograph by Daniels.)
of three or four hundred eggs on the surface of wounds, and in the ears and nasal fossæ (Fig. 214) of persons sleeping in the open air, especially of those having offensive discharges, which attract the fly. From these eggs the larvæ are hatched in a few hours. The larvæ (Fig. 213) are white, about three-quarters of an inch in length, and formed of twelve segments carrying circles of minute spirally arranged spines which give the creature a screw-like appearance; hence the vulgar name. They burrow in the tissues, devouring the mucous membrane, muscles, cartilages, periosteum, and even the bones, thereby causing terrible sores, and not infrequently—particularly when they attack the ear or nasal fossæ, by penetrating to the brain
Fig. 215.—Dermatobia cyaniventris, female.
—death. Of 13 cases collected by Laboulbène 9 proved fatal; of 31 collected by Maillard 21 died.
If treated properly and in time by injections of chloroform, carbolic acid, turpentine, infusion of pyrethrum, and similar substances, the patient may be saved; neglected, he will most
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| Fig. 216.—Dermatobia cyaniventris, larva, early stage. (Blanchard.) |
Fig. 216a.—Dermatobia cyaniventris, larva, later stage. (After Brauer.) |
probably die. If necessary the frontal sinuses, the antrum, and other bony cavities must be opened to secure the expulsion of the larvæ.
In countries where this pest occurs bloody and offensive discharges from the nostrils should be carefully investigated, and, if found to be caused by the screwworm, vigorously treated.
Ver Macaque (Dermatobia cyaniventris)
This is the larva of an American fly (Fig. 215) the identity of which, until it was studied by Blanchard, was doubtful.
At an early stage the larva has the appearance represented by Fig. 216; at a later stage, that represented by Fig. 216a. The former stage of the larva is called ver macaque; the latter, much larger, torcel or berne. At one time these two larval stages of the same insect were erroneously supposed to belong to different species.
Dermatobia cyaniventris measures from 14 to 16 mm. in length; it has a yellow head with very prominent brown eyes;
Fig. 217.—Janthinosoma lutzi. (By courtesy of the Tropical Diseases Bureau.)
the thorax is of a greyish colour, the abdomen of a dark metallic blue. It is widely distributed throughout tropical America, being especially common near wooded lands. It attacks the most diverse animals. Commonly it is found in cattle, pigs, and dogs, but it occurs in the agouti, in the jaguar, in various monkeys, and in birds. It is rare in the mule, and writers have commented upon its absence from the horse. In man it has been reported from various regions of the body, namely, head, arm, back, abdomen, scrotum, buttocks, thigh, axilla. Its presence is accompanied by excruciating pains, especially at those times when the larva is moving.
Blanchard, Surcouf, and Zepeda have recently thrown a curious light on the way in which this myiasis is acquired. It would appear that on attaining maturity Dermatobia cyaniventris lays its eggs on damp leaves in damp places, the haunts of a certain species of mosquito, Janthinosoma lutzi (Fig. 217). The packets of eggs are enclosed in a cement which on becoming softened by moisture adheres to the mosquito's thorax, and the eggs are thus conveyed to man or other vertebrate when the mosquito next proceeds to feed.
Fig. 218.—Cordylobia anthropophaga.
It is supposed that when hatched out the larvæ penetrate the skin and produce an inflamed swelling about the aperture of entrance, from which a seropurulent fluid, containing the black fæces of the larva, exudes. Depied says that he has twice encountered this larva in the scalp of Tonquinese.
Fig. 219.—Cordylobia anthropophaga, larva.
Ver du Cayor (Cordylobia anthropophaga)
Synonym.—Ochromyia anthropophaga.
Cordylobia anthropophaga (Fig. 218) measures from 8·5 to 11·5 mm. in length. It is of a yellowish-grey colour, with black spots on the abdomen. It was first reported from Cayor, Senegambia, but it is probably widely distributed in tropical Africa. The larva (Fig. 219) burrows into the skin of man and beast, and produces a small inflamed swelling, from which it emerges in from six to seven days.
In Africa, and in many other parts of the tropical world, similar anthropophagous larvæ, which, however, have not yet been satisfactorily identified, are frequently encountered. According to Griinberg all these larvæ belong to one species—Cordylobia anthropophaga; on the other hand, Gedoelst distinguishes four different species—Ochromyia anthropophaga, Bengalia depressa (widely distributed), Cordylobia anthropophaga (German East Africa), and a larva of undetermined species— Lund's" larva (Congo Free State).
AUCHMEHOMYIA LUTEOLA (Fabricius, 1805)
Synonym.—Musca luteola.
History.—Auchmeromyia luteola was first described by Fabricius in 1805 under the name of Musca luteola. In January, 1904, Captain Lelean described and figured this fly, which he had collected and reared from the larva while on service with the Anglo-French Boundary Commission in Northern Nigeria. He stated that the larva occurs as a cutaneous parasite on natives near Sokoto. In July of the same year, at the Oxford meeting of the British Medical Association, Button, Todd and Christy gave a more detailed account of the life habits of this dipterous insect, and pointed out that in its larval stage it is a keen blood-sucker, and is known throughout the Congo as the " Congo floor maggot."
Geographical distribution.—Auchmeromyia luteola is widely distributed throughout tropical Africa. On the "West Coast it ranges from Northern Nigeria to Natal. Button, Todd and Christy found it all over the Lutete and surrounding districts, and at Leopold ville. They were told that it is common at San Salvador in Portuguese territory, on the Congo at Matadi in the cataract region, and at Tchumbiri, 150 miles above Stanley Pool. An intelligent native from Lake Tchad informed them that it was common in Western Tchad regions. It was found by Neave in the Soudan.
Specific diagnosis (Fig. 220).— The fly measures from 10 to 12 mm. in length, and its body is rather stoutly built. The general colour is orange-buff, but numerous small black hairs give it a smoky appearance. The head is large, with eyes well separated in both sexes. The thorax shows two indistinct, dark, longitudinal stripes, which do not reach its posterior border. The abdomen differs in the two sexes, the second segment in the female being twice the length of the same segment in the male. The first segment has a narrow dark stripe on its hind margin in both sexes; the second segment in the male is marked by a broader band, tapering forwards along the middle line to the base of the segment. In the female the dark band is so wide that it occupies almost the whole segment. The third segment is almost entirely black in both sexes. The fourth is dark at the base and lighter posteriorly. The legs are the same colour as the rest of the body. The first tarsal joint is jet black, and stands out prominently against the large cream-white pulvillus. The wings are of a smoky-brown colour with conspicuous venation.
The larva (Fig. 221) is of a dirty-white colour and semi-translucent. It consists of eleven distinct segments, and when fully grown measures about 15 mm. in length. The central part
Fig. 220.—Aucmaeromyia luteola, female.
of the ventral surface is flattened. At the posterior margin of each segment are three short limbs transversely arranged and provided with spines directed backwards. These enable the maggot to move about caterpillar-like and fairly rapidly. Laterally the segments bear two or more irregular protuberances, each of which has a posteriorly directed spine and a
Fig. 221.—Auchmeromyia luteola, larva.
small pit. The anterior segment is roughly conical, and bears the mouth, which is placed between two black hooks protruding from its apex and curved backwards towards the ventral surface of the body. Paired groups of minute teeth are placed around the two hooks so as to form a sort of cupping apparatus. The last segment is larger, depressed, and turned upwards at an angle of about 45 degrees with the rest of the body; two spiracles open on its dorsal surface, which is surrounded by spines. The anus is placed in the anterior portion of its ventral surface, and behind it are two prominent spines. The alimentary canal commences with a short œsophagus, which ends in a proventriculus. A remarkable dorsal diverticulum, corresponding to the food reservoir of the muscid larva, opens into the œsophagus near its anterior end. After the larva has fed, the diverticulum is a very conspicuous object, being seen through the semitransparent body wall as a bright-red area, extending, when full of blood, from the head to about the fifth segment. The midgut is short; the hindgut is long, much coiled, and occupies the greater part of the body cavity. The maggot has a thick integument, which enables it to withstand a good deal of pressure without injury.
The duration of the larval period has not been determined. When ready to pupate, the larva selects a suitable spot and lies dormant. The puparium is a dark reddish-brown oblong body, measuring 9-10.5 mm. in length by 4-5 mm. in breadth. The anterior end is roughly conical; the posterior is rounded. The pupa stage lasts from two to three weeks.
The fly is usually found sitting motionless amongst the thatch, beams, and cobwebs of the walls and roofs of native huts, but it is very difficult to see on account of its protective colouring, which corresponds exactly with the smoke-stained straw and rafters. It never bites, is usually silent, and deposits its eggs in the dust-filled cracks and crevices of the mud-floors of the huts, particularly in spots where urine has been voided.
The larvæ are found especially under the mats on which the natives sleep, in the floor crevices, and in moist soft earth at a depth of 3 in. or more. According to Bentley, as many as fifty could sometimes be found beneath a single mattress. They feed mainly or entirely at night, and they drop off at once if the limb on which they are feeding is moved. Those who sleep on beds or raised platforms are not attacked as a rule unless the bed be low, when the maggot may reach the occupant by crawling 1 up either the supports or the grass wall against which the bed is usually placed. The natives state that the maggot is able to jump to a height of 18 in., but this is unlikely.
LEECHES
In the grass and jungle lands of many tropical and sub-tropical countries land-leeches, probably of special species, often occur in great abundance; so much so that in some circumstances they may prove to be something more than a nuisance. The Hœmadipsa ceylonica is one of the most active, as well as best known, of these. Before feeding, when outstretched, it is about an inch in length and about the thickness of a knitting-needle. It clings to a leaf or twig, awaiting the passing of some animal, on to which it springs with remarkable activity. It at once attaches itself to the skin, and proceeds to make a meal on the blood. Animals are sometimes killed in this way; men even have been known to succumb to the repeated small bleedings by these pests. It is necessary, therefore, when passing through jungle hinds in which leeches abound, to have the feet and legs carefully protected. The bite is not infrequently the starting-point of a troublesome sore.
In the south of Europe and in the north of Africa the horse-leech, Hœmopis sanguisuga, sometimes gets into the gullet and nostrils of men as well as of animals. It has occasionally caused death by entering and occluding the air-passages. In Formosa I heard of and saw several instances of a similar form of parasitism, both in men and in monkeys. To what particular species the leech in these cases belonged I do not know. Doubtless, when very young the leeches were taken in unperceived with foul drinking-water, and, wandering round the soft palate, found their way into the nose. Occasionally, in the cases I refer to, the animals would protrude from the nares and wander over the upper lip. For a long time they contrived to elude all attempts at capture. By dipping the face in cold water they could generally be persuaded to show themselves. In one instance the leech dropped out spontaneously. In another— an American naturalist who had been travelling much in the interior of Formosa, and who had suffered from severe headache and profound anæmia, the results of repeated epistaxis— I succeeded in removing the leech by attaching through a speculum a spring forceps to its hinder end, and afterwards injecting salt and water. It would be well, therefore, to bear in mind that in tropical countries persistent headache, associated with recurring epistaxis, may be caused by a leech in the nostril.
- ↑ * It is difficult from his description to determine the exact nature of the disease alluded to by Legrain. It commences with pronounced fever lasting for one week, and is followed by malaise persisting for several weeks. This is followed by itching and, by and by, by furfuraceous desquamation of the itching parts and gradually developed achromia. He positively affirms that the disease is not ordinary vitiligo. He also says he has seen in Tripoli a coloured skin affection with the clinical features of true pinta occurring in little epidemics in particular houses. The results of microscopical examinations of scrapings of the affected skin were negative. Possibly this is the disease referred to in the Journ. of Trap. Med., Nov., 1899, by Sandwith, as having been seen by him in Egypt. Varieties of pityriasis versicolor, such as Castellani has described in Ceylon, may have been mistaken sometimes for true pinta.