Febrile ulceronecrotic Mucha-Habermann disease is a severe variant of pityriasis lichenoides et varioliformis acuta characterized by the sudden onset of ulceronecrotic skin lesions and associated with high fever and systemic symptoms. We report here a case of a 20-year-old woman in whom the disease started as pityriasis lichenoides et varioliformis acuta and evolved to febrile ulceronecrotic Mucha-Habermann disease. Almost 90% of the body surface was involved, together with high fever and malaise. Steroids alone proved to be an insufficient therapeutic procedure. The remission achieved was attributed to the use of methotrexate. To our knowledge, only 39 cases of febrile ulceronecrotic Mucha-Habermann disease have been reported in the literature to date.