#Does the eruption of erythema multiforme ever assume a vesicular or bullous character?#
Yes. In exceptional instances, the inflammatory process may be sufficiently intense to produce vesiculation, usually at the summits of the papules--_erythema vesiculosum_; and in some instances, blebs may be formed--_erythema bullosum_. A vesicular or bullous lesion may become immediately surrounded by a ring-like vesicle or bleb, and outside of this another form; a patch may be made up of as many as several such rings--_herpes iris_. In the vesicular and bullous cases the lips and the mucous membranes of the mouth and nose also may be the seat of similar lesions.
#What is the course of erythema multiforme?#
Acute, the symptoms disappearing spontaneously, usually in one to three or four weeks. In some instances the recurrences take place so rapidly that the disease assumes a chronic aspect; it is possible that such cases are midway cases between this disease and dermatitis herpetiformis.
#Mention the etiological factors in erythema multiforme.#
The causes are obscure. Digestive disturbance, rheumatic conditions, and the ingestion of certain drugs are at times influential. Intestinal toxins are doubtless important etiological factors in some cases. Certain foods, such as are apt to undergo rapid putrefactive or fermentative change, especially pork meats, oysters, fish, crabs, lobsters, etc., are, therefore, not infrequently of apparent causative influence. It is most frequently observed in spring and autumn months, and in early adult life. The disease is not uncommon.
#What is the pathology of erythema multiforme?#
It is a mildly inflammatory disorder, somewhat similar to urticaria, and presumably due to vasomotor disturbance; the amount of exudation, which is variable, determines the character of the lesions.
#Name the diagnostic points of erythema multiforme.#
The multiformity of the eruption, the size of the papules, often its limitation to certain parts, its course and the entire or comparative absence of itching.
It resembles urticaria at times, but the lesions of this latter disease are evanescent, disappearing and reappearing usually in the most capricious manner, are commonly seated about the trunk, and are exceedingly itchy.
