Febrile ulceronecrotic Mucha-Habermann disease in an 8-year-old boy responding to methotrexate.

Background: Febrile ulceronecrotic Mucha-Habermann disease (FUMHD) is a rare fulminant variant of pityriasis lichenoides et varioliformis acuta (PLEVA) characterized by a rapidly progressive course with predominant ulceronecrotic lesions associated with fever and systemic manifestations. First described by Degos in 1966, it carries a high morbidity and is potentially fatal. The exact pathogenesis is not clear, but it is proposed to be the result of hypersensitivity reaction to an infection.