Erythema Multiforme

The eruption of erythema multiforme is a diffused patch of redness over which circumscribed elevations, also red, are scattered. These elevations may be few or plentiful, and may be from an eighth to three-quarters of an inch in diameter. The small ones, according to size, may be called papules or tubercles, while the larger ones, which are always flattened, may assume the appearance of an elevated ring, around which a second or a third ring may develop. On the flattened tubercles, of medium size, vesicles are sometimes met with, and hemorrhagic effusions may also occur within them.

These lesions rarely persist for more than a few days, or at most a week or so, at the end of which time they gradually subside and disappear, leaving after them slight stains, which last a few days longer. After the disappearance of the first eruption or even while it is still in full bloom, a second crop of lesions may come out, and after these a third, prolonging the trouble in this way for several weeks and even months. Two or more of the lesions mentioned may coexist, and the eruption may appear on any part of the surface, but as a rule it prefers the extremities. Slight febrile action may precede the development of the eruption, but it soon disappears, and there is rarely any accompaniment other than slight itching. The causes of erythema multiforme are obscure; occasionally it appears due to errors of diet, and sometimes also to uterine disorder. The prognosis is favourable, so far as any trouble may result from the eruption; but when it is prolonged for weeks, as is sometimes the case, it proves very annoying. It attacks by preference the backs of the hands and feet, the arms, the legs, and the forehead. It is mostly an affection of children and young people. It attacks females more than males, and prevails in the spring and fall. Individuals who are troubled with it one year are apt to have it again at the same time in succeeding years. When occurring on the fingers it closely resembles chilblains. It may be commonly known by its superficial and protean character, and its symmetrical distribution.