Cutaneous Hemophagocytosis in a Sweet Syndrome—An Unusual Phenomenon in a Rare Guise

Cutaneous hemophagocytosis is typically known as skin manifestation of syndromal hemophagocytic lymphohistiocytosis, which presents with fever, splenomegaly, cytopenia, hyperferritinemia, and hypertriglyceridemia. Pathophysiologically, an ineffective pathogen elimination has been postulated, which is compensated by excessive macrophage activation. In this study, we present an unusual case of skin limited cutaneous hemophagocytosis within a rare manifestation of a Sweet syndrome triggered by an upper respiratory infection and drug cofactors. A 38-year-old female patient presented with a painful skin rash and a right swollen knee joint that occurred after the onset of streptococcal angina treated with amoxicillin and acetylsalicylic acid. Skin lesions presented as succulent livid red plaques from the forehead to the extensor sides of the upper arms. Clinically, a classical Sweet syndrome was diagnosed by postinfectious onset, distribution and morphology of skin lesions, and abnormal laboratory values including neutrophilic leukocytosis. Histopathologic examination revealed typical characteristics of an acute Sweet syndrome but further showed hemophagocytosis of neutrophils and eosinophils by macrophages. There was a rapid regression of the complaints and skin lesions under systemic high-dose prednisone therapy. Extensive investigations are recommended only if indicators for a syndromal hemophagocytic lymphohistiocytosis are present.