[Sweet syndrome with immune complex vasculitis in a child].

We report on a rare case of Sweet's syndrome (SS) in a 7-year-old boy showing typical symptoms such as high fever, neutrophil leucocytosis in peripheral blood, elevated blood sedimentation rate, and arthralgia. The cutaneous lesions were painful erythematous, raised plaques on both limbs and the face. Histology confirmed the clinical diagnosis, including remarkable signs of cutaneous small vessel vasculitis, which was verified by direct immunofluorescence for IgM and complement (C3) in vessel walls as well as by the presence of circulating immune complexes in the blood. By means of monoclonal antibodies, T-lymphocytes and macrophages could be identified in the perivascular infiltrates in the delayed phase of SS. According to these immunological findings, we discuss the pathomechanism and the therapeutical benefit of inhibitors of cyclooxygenase.