Febrile ulceronecrotic Mucha‐Habermann disease mimicking Kawasaki disease

Abstract

Febrile ulceronecrotic Mucha-Habermann disease (FUMHD) is a rare and fulminant variant of pityriasis lichenoides et varioliformis acuta (PLEVA) characterized by fever, severe and rapidly progressive ulcerative and necrotic skin lesions with systemic involvement. Febrile ulceronecrotic Mucha-Habermann disease is considered to be part of the spectrum of pityriasis lichenoides, a continuum of inflammatory skin disorders with unresolved pathogenesis [1–4]. To date, only 70 cases of FUMHD have been reported, with predominance in children and adolescents [1, 4, 5]. Unfamiliarity among physicians due to the rarity of the disease may result in delayed or incorrect diagnosis of FUMHD, with a potentially fatal outcome [4]. Due to cardiovascular, hematologic, gastrointestinal, and neurological complications, the mortality rate of FUMHD increases with age up to 15–20 % [5–7]. We report the youngest case of FUMHD so far, initially presenting as Kawasaki disease (KD) and successfully treated with methylprednisolone and methotrexate (MTX) [8]. A 9-month-old infant was admitted due to persistent fever over five days, with an acute diffuse maculopapular exanthematous rash covering the face, trunk and extremities (Figure 1). The boy also had cervical lymphadenopathy, bilateral conjunctivitis with erythema of the oral mucosa, lips (Figure 1a), tongue and glans penis. On examination, he was febrile (39.1°C) and in poor general condition. Auscultation revealed slight rales. His medical history was unremarkable and he had not received any medication before the onset of fever. Laboratory findings on admission showed an elevated CRP (85 mg/L) and microcytic anemia. The white blood cell count and routine chemistry, coagulation studies as well as ANA, ANCA and immunoglobulins were all within normal limits. No viral or bacterial infection could be detected by swabs, blood culture, serology (HSV, VZV, measles, mycoplasma) or PCR (VZV, adenovirus). The chest x-ray, abdominal ultrasound, ECG, and echocardiography were unremarkable. Since the initial diagnosis was KD, treatment with intravenous immunoglobulins (IVIGs 2 g/kg; 19 g/d) and aspirin (20 mg/kg; 200 mg/d) was initiated. Despite this intervention, the patient remained febrile and the exanthema quickly transitioned to papulovesicular and ulcerative papules and plaques with predominantly acral und mucosal involvement (Figures 2, 3). A skin biopsy from the forearm revealed lichenoid dermatitis with degeneration of the basal layer, multiple apoptotic keratinocytes and a dense, predominantly CD8+ lymphocytic infiltrate, highly specific for pityriasis lichenoides (Figure 4). Febrile ulceronecrotic Mucha-Habermann disease was diagnosed based on the acute clinical presentation. Apart from the laboratory abnormalities, there was no sign of other systemic involvement. Treatment was switched to oral methylprednisolone (1 mg/kg; 10 mg/d), MTX (15 mg/ m2 BSA; 7.5 mg/week) and folic acid (5 mg/week). Methylprednisolone was gradually tapered off over six weeks, while the latter two medications were continued until remission was stable (treatment duration three months). Most strikingly, the fever decreased dramatically following the first administration of methylprednisolone, and the patient’s general condition and inflammatory markers improved rapidly. The skin lesions resolved gradually within three weeks, leaving DOI: 10.1111/ddg.13989 Febrile ulceronecrotic Mucha-Habermann disease mimicking Kawasaki disease Clinical Letter