Abstract
A 7-year-old girl developed skin eruption of maculopapular, erythematous and purpuric lesions on the face, elbows, and knees. In addition, palpable purpuras were present on the legs and the dorsum of the feet. Antineutrophil cytoplasmic autoantibodies (ANCA) with antimyeloperoxidase specificity (MPO-ANCA) were positive. Microscopic hematuria was detected but a renal biopsy specimen disclosed no abnormalities. A skin biopsy from a palpable purpura showed leukocytoclastic vasculitis of the small vessels in the entire dermis. The patient was diagnosed as having microscopic polyangitis (MPA). After methylprednisolone pulse therapy, treatment with oral prednisolone was started, resulting in complete regression of all symptoms, including skin lesions and disappearance of MPO-ANCA. However, the nodules on the knee reappeared with a concomitant rise in MPO-ANCA. The dose of prednisolone was increased and mizoribine was added. The combined therapy improved the nodules on the knee with disappearance of MPO-ANCA. However, the nodules on the knee have never completely regressed and they have intermittently worsened and are associated with slight elevation of MPO-ANCA. In the present patient, the severity of skin lesions correlated well with the levels of MPO-ANCA, suggesting that MPO-ANCA may play a role in the pathogenesis of the skin lesions.Skin Research, 11: 202-208, 2012
