nodosum erythema causeserythema nodosum sarcoidosis picturesrecurrent erythema multiformeerythema multiforme behandlingatypical erythema multiformeerythema multiforme contagiouserythema nodosum etiologyurticaria erythema multiformeerythema multiforme lesionsmycoplasma erythema multiformesevere erythema multiformeerythema multiforme pediatric