ALOPECIA AREATA.
Alopecia areata is an affection of frequent occurrence in childhood, and one which the family physician should be competent to recognize and to treat. To say that he should be able to treat a case as successfully as any specialist is not making a great claim, when we consider how little positive knowledge is possessed by the latter concerning the cause and cure of this not uncommon disease.
As the name indicates, alopecia areata implies the occurrence of baldness in spots; but all bald areas are not necessarily cases of alopecia areata. Before describing the affection itself it may be well to refer briefly to certain forms of baldness, areate or complete, which are often improperly classed as cases of the disease in question.
When infants are born without hair, and for years, perhaps, exhibit but a sparse capillary growth, coincident usually with imperfect dental development, this condition is not to be regarded as alopecia areata and the term is not apt to he applied.
When, as a result of injury, fright, or intense mental excitement, the hair falls suddenly from the scalp, or from the whole body in the case of adults, we have a condition which is by no means one of true alopecia areata, although in such cases the name is very apt to be misapplied.
When, from injury to a nerve, an irregular patch of baldness develops upon the portion of hairy skin which the nerve supplies, the condition is one which strongly resembles the disease in question. It differs, however, from true alopecia areata in several essential points. It usually lacks the rounded outlines, it does not tend to spread or duplicate itself at other points, and the hairs at the margin of the bald area are not loosened. It is a bald patch of evident neurotic origin, but should be distinguished from alopecia areata.
A rare form of scalp disease, known as folliculitis decalvans,
