Heredity plays a small part in pro ducing early alopecia. Only four incon testable instances were found in over three hundred cases treated. Over DO Per cent. are due to the one disease: eczema seborrhceicurn. Two varieties of diplococci isolated, both of which inoc ulated upon healthy subjects produced lesions characteristic of the disease. One was a non-chromogenic organism which produced pityriasic manifestations; the other, chromogenic, produced lesions cov ered with yellowish, greasy scales. Both together cause greasy, crumbling scales. Elliot (Amer. Derm. Assoc., Sept. 17 to 19, '93). Trichophylosis.—Microscopical exami nation in this disease shows at once that no distinct parasite is found in alopecia areata, while in trichophytosis the hair is filled with spores. The hairs, when seized with forceps, become crushed, while they do not yield in alopecia areata.
Case of a boy presenting a perfectly bald spot about two inches in diameter on the top of the head, with the typical features and hair of alopecia areata. It had begun, however, as a scaly patch. Miscroscopical examination showing the presence of spores, it was pronounced to be trichophyton by Bulkley. White house (Jour. Cut. and Genito-Urin. Dis., Oct., '93).
Etiology. — In the great majority of cases alopecia areata occurs as a result of contagion. This has been fully dem onstrated clinically and experimentally. The implements of the hair-dresser are almost the only agents of transmission of contagion, doubtless because they alone can cause the abrasions necessary for sowing the organism with which con tamination occurs. This explains why alopecia areata seems, at first sight, to be a sporadic affection in cities, and why in colleges and barracks it may take the shape of an epidemic. Every disease , • propagated from one individual to other supposes an active cause capable of multiplication and reproduction: that is to say, a living pathogenic parasite.
There is a close relationship between tines tonsurans and alopecia arca ta. Cases with all the signs of alopecia areata may arise, not in children only, but in adults, from contact with ordi nary tinea tonsurans. It is not the bald form of tinea tonsurans, because the short hairs, as in alopecia areata, are club-shaped, whereas, in tinea tonsurans, they are bent and twisted. Crocker (Lancet, Feb. 23, Mar. 7, '91).
Ringworm and alopecia areata are in many ways connected. Of 137 cases of the latter seen by the author, 32 per cent.
gave a history of ringworm, either per sonal or occurring in some member of the household. P. Abrahams (Med. Press and Circular, Nov. 22, '93).
Eight boys, all between the ages of 12 and 13, belonging to the same gym nasium—six in one class and two in an other—were within a very short time attacked with a most typical alopecia areata: the hair fell out, while the skin remained perfectly smooth without the formation of any crusts or scabs. All the six pupils were sitting near one an other on the same bench. This epidemic proves the contagiousness of alopecia areata beyond any question. Kober (Berliner klin. Woch., No. 15, '98).
Conviction expressed that alopecia areata is contagious under certain cir cumstances. Lassar (Phila. Med. Jour., Apr. 16, '98).
Two epidemics of alopecia areata in an institution for homeless girls between the ages of 3 and 14 years. The first case occurred in a girl, 11 years old, who, when first seen, presented three round, bald patches upon the crown of the head, clinically typical of alopecia areata. Several weeks later another girl was found to have a bald patch upon the crown, which increased rapidly in size for a time. Four months after the dis covery of the first case a large number of the girls in the asylum were suddenly found to be affected. After cutting the hair of all the children it was found that 63 of the 69 girls had bald areas upon the scalp. One girl, who had just entered the institution, acquired a patch in three days. After two months the disease ap peared to come to a stand-still; at the end of six months almost all the bald patches were covered with hair. No trace of micro-organism was found. No adult inmate of the asylum was attacked. Bowen (Jour. Cutan. and Genito-Urin. Dis., Sept., '99).
Alopecia areata may also be caused by shock, worry, overwork, traumatisms, or epileptic paroxysms.
Case following prostration through shock, continued until there was com plete denudations of hairy portions of the body. Morton (Brooklyn Med. Jour., Sept., '95).
Two instances of alopecia areata oc curring in epileptics after paroxysms, in which the neurotic rather than the para sitic origin seems the more probable. The hairs finally recovered their thick ness, volume, and color. In both cases alike the evolution of the lesions was not interfered with by any medical in tervention, either general or local. Fere (La Nouv. Iconog. de la Salpetri&re, '95).