[Urticaria multiforme is a variation of urticaria, which imitates erythema multiforme].

A 21-month-old boy developed urticaria multiforme during the course of a presumed pneumonia, which was treated with imacillin. At admission to hospital he was initially considered to have erythema multiforme, but the correct diagnosis was soon established as urticaria multiforme. He had a good response to antihistamines. The diagnostic differences between urticaria multiforme and erythema multiforme are presented in this case report.