The etiology is obscure. Two theories as to the cause of the disease exist: one of these regards it as parasitic, and the other considers it to be trophoneurotic. Doubtless both are right, as a study of the literature would indicate that there are, as regards etiology, really two varieties--the contagious and the non-contagious. In America examples of the contagious variety are uncommon.

Does the skin undergo any alterative or destructive changes?

Microscopical examination of the skin of the diseased area shows little or no alteration in its structure beyond slight thinning.

How do you distinguish alopecia areata from ringworm?

The plaques of alopecia areata are smooth, often completely devoid of hair, and free from scales; while those of ringworm show numerous broken hairs and stumps, desquamation, and usually symptoms of mild inflammatory action. In doubtful cases recourse should be had to the microscope.

What is the prognosis in alopecia areata?

The disease is often rebellious, but in children and young adults the prognosis is almost invariably favorable, permanent loss of hair being uncommon. The same holds true, but to a much less extent, with the disease as occurring in those of more advanced age. In extensive cases--those in which the hair of the entire scalp finally entirely disappears, and sometimes involves all hairy parts--the prognosis is unfavorable. Only exceptionally does recovery ensue in such instances.

The uncertain duration, however, must be borne in mind; months, and in some instances several years, may elapse before complete restoration of hair takes place. Relapses are not uncommon.

How is alopecia areata treated?

By both const.i.tutional and local measures, the former having in view the invigoration of the nervous system, and the latter a stimulating and parasiticidal action of the affected areas.

Give the const.i.tutional treatment.

a.r.s.enic is perhaps the most valuable remedy, while quinine, nux vomica, pilocarpine, cod-liver oil and ferruginous tonics may, in suitable cases, often be administered with benefit.

Name several remedies or combinations employed in the external treatment of alopecia areata.

Ointments of tar and sulphur of varying strength; the various mercurial ointments; the tar oils, either pure or with alcohol; stimulating lotions, containing varying proportions, singly or in combination, of tincture of capsic.u.m, tincture of cantharides, aqua ammoniae, and oil of turpentine. The following is a safe formula, especially in dispensary and ignorant cla.s.s practice:

[Rx] [beta]-naphthol, ..................... [dram]ss-[dram]j Ol. cadini, .......................... [dram]j Ungt. sulphuris, .......... q. s. ad ... [Oz]j M.

The cautious use of a five to twenty per cent. chrysarobin ointment is of value. Painting the patches with pure carbolic acid or trikresol every ten days or two weeks sometimes acts well; it should not be applied over large areas nor used in young children. Galvanization or faradization of the affected parts may also be employed, and with, occasionally, beneficial effect. Stimulation with the high-frequency current by means of the vacuum electrode is also of value. When practicable, the Finsen light can be applied with hope of benefit and cure.

Atrophia Pilorum Propria.

(_Synonym:_ Atrophy of the Hair.)

What do you understand by atrophy of the hair?

An atrophic, brittle, dry condition of the hair, and which may be either symptomatic or idiopathic.

Describe the several conditions met with.

As a symptomatic affection, the dry, brittle condition of the hair met with in seborrh[oe]a, in severe const.i.tutional diseases, and in the various vegetable parasitic affections, may be referred to.

As an idiopathic disease it is rare, consisting simply of a brittleness and an uneven and irregular formation of the hair-shaft, with a tendency to split up into filaments (_fragilitas crinium_); or there may be localized swelling and bursting of the hair-shaft, the nodes thus produced having a shining, semi-transparent appearance (_trichorrhexis nodosa_). This latter usually occurs upon the beard and moustache.

State the causes of atrophy of the hair.

The causes of the symptomatic variety are usually evident; the etiology of idiopathic atrophy is obscure, but by many is thought due to parasitism.

[Ill.u.s.tration: Fig. 39. Trichorrhexis Nodosa. (_After Michelson._)]

What would be your prognosis and treatment in atrophy of the hair?

Symptomatic atrophy usually responds to proper measures, but always slowly; treatment is based upon the etiological factors.

For the idiopathic disease little, as a rule, can be done; repeated shaving or cutting the hair has, in exceptional instances, been followed by favorable results.

Atrophia Unguis.

(_Synonyms:_ Atrophy of the Nails; Onychatrophia.)

Describe atrophy of the nails.

The nails are soft, thin and brittle, splitting easily, and are often opaque and l.u.s.treless, and may have a worm-eaten appearance. Several or more are usually affected.

State the causes of atrophy of the nails.

The condition may be congenital or acquired, usually the latter. It may result from trauma, or be produced by certain cutaneous diseases, notably eczema and psoriasis; or it may follow injuries or diseases of the nerves. Syphilis and chronic wasting const.i.tutional diseases may also interfere with the normal growth of the nail-substance, producing varying degrees of atrophy. The fungi of tinea trichophytina and tinea favosa at times invade these structures and lead to more or less complete disintegration--_onychomycosis_.

[Ill.u.s.tration: Fig. 40. Atrophy of the Nails.]

What is the treatment of atrophy of the nails?

Treatment will depend upon the cause. When it is due to eczema or psoriasis, appropriate const.i.tutional and local remedies should be prescribed. If it is the result of syphilis, mercury and pota.s.sium iodide are to be advised. In onychomycosis--an exceedingly obstinate affection--the nails should be kept closely cut and pared, and a one- to five-grain solution of corrosive sublimate applied several times a day; a lotion of sodium hyposulphite, a drachm to the ounce, is also a valuable and safe application.

Atrophia Cutis.

(_Synonyms:_ Atrophoderma; Atrophy of the Skin.)

What do you understand by atrophy of the skin?