An acute respiratory infection precedes the purpura in a high proportion of affected young children. Less commonly, a drug appears to be the inciting agent. The disease begins abruptly with the sudden appearance of a purpuric skin rash involving primarily the extensor surfaces of the feet and legs, a strip across the buttocks, and the extensor surfaces of the arms. Crops of new lesions may appear over days to several weeks. Most patients also have fever and plyarthralgia with associated periarticular tenderness and swelling affecting the ankles, knees, hips, wrists and elbows.
Many patients also develop edema of the hands and feet.
GI findings are common and include colicky abdominal pain, abdominal tenderness and melena or stool tests positive for occult blood. The disease usually remits after about 4 wk but often recurs one or more times after a disease-free interval of several weeks. The diagnosis is based largely on recognition of the clinical findings. Renal biopsy may help define the prognosis of the renal lesion. Treatment, except for the elimination of a possible offending drug, is primarily symptomatic.