Histiocytoid Sweet syndrome

A 48‐year‐old man presented with a 3‐day history of a rapidly progressing painful and pruritic cutaneous eruption and fever. He had used methamphetamine a week before the eruption. His past medical history was otherwise unremarkable. The eruption was photodistributed, with erythematous to violaceous papules and pseudo‐bullae in the face, ears, neck, upper chest and the dorsal aspect of his forearms and hands (Figure, A and B). He was febrile and tachycardic. Full blood count revealed a neutrophilia. An infective screen was negative. Biopsies demonstrated subepidermal oedema and a dense dermal infiltrate composed of neutrophils, histiocytes and lymphocytes, consistent with histiocytoid Sweet syndrome. Solid organ and haematological malignancy screening were negative. He was treated with prednisolone 30 mg daily and topical emollient therapies, with resolution of his fevers and cutaneous eruption within 10 days. Histiocytoid Sweet syndrome can be idiopathic, associated with underlying malignancy, or drug‐induced.1,2