Incidence of EM major is 0.8-6.0 per million per year. Morbidity and mortality are attributable to complications of EM major, which are described below. Uncomplicated EM major usually resolves spontaneously in 2-4 weeks. Incidence of drug-related cases of EM major is equal in males and females. Lesions may coalesce and become generalized.
Vesiculobullous lesions develop within preexisting macules, papules, or wheals.
Rash favors palms and soles, dorsum of the hands, and extensor surfaces of extremities and face. Resolution usually occurs over 7-10 days. Postinflammatory hyperpigmentation or hypopigmentation may occur. Fever is common. Skin findings may be similar to EM minor but often are more variable and severe.