11-year-old boy presented...

An 11-year-old boy presented with an erythematous papule on his trunk that had been present for two weeks. Without invasive necrotic scars, he had a densely distributed, soy-sized, erythematous maculopapular rash on his trunk and extremities. The oral and genital mucosa were not affected. The diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) was made based on clinical features and skin biopsy. Laboratory findings were normal except for a decreased white blood cell count (3.9 × 10^9/L). The chest X-ray was normal, and the virus and bacterial infection screening were negative. The patient was started on mometasone furoate cream and tacrolimus ointment for four days, but new rashes appeared, presenting with extensive pain, necrotic ulcerated papules, and plaques, especially loose pustules in the groin, perineum, neck, and axilla, with a fever of 39°C. A follow-up blood test revealed CRP (14 mg/L), aspartate aminotransferase (117 U/L), and alanine aminotransferase (54 U/L), respectively. A skin culture was positive for methicillin-resistant Staphylococcus aureus (MRSA) and Pasteurella aerogenes. Based on the clinical findings diagnosis of Febrile ulceronecrotic Mucha-Habermann disease (FUMHD) was made.