[Successful treatment of allergic purpura nephritis associated with thrombotic microangiopathy using plasma exchange: a case report].

A 73-year-old man, who had an allergy to shellfish, was admitted to our hospital because of proteinuria, hematuria, purpura and extremity edema after eating oysters. Laboratory data on admission were proteinuria 2.0 g/day, hematuria 3+, serum creatinine (Cr) 1.2 mg/dl, total protein 6.3 g/dl, and albumin 3.1 g/dl. He presented a high fever with neutrophilia and rapid deterioration of renal function after admission. Based on the skin biopsy, we made a diagnosis of leukocytoclastic vasculitis with IgA deposition. Oral prednisolone (40 mg/day) following drip intravenous methylprednisolone (500 mg/day, 3 days) was administered. However, renal function and urinary findings showed no sign of improvement. In the first renal biopsy, although there were no crescentic formations, most of the glomeruli showed thrombotic microangiopathy and endocapillary proliferation with IgA deposition and electron dense deposits. Therefore, a plasma exchange was performed resulting in an improvement of the renal function. The serum Cr. level was reduced from 2.7 to 0.8 mg/dl and proteinuria from 3.7 to 0.1 g/day. In the second biopsy, the electron dense deposits with an IgA deposition had disappeared. These findings suggested that plasma exchange was effective in leading remission in a case of allergic purpura nephritis associated with thrombotic microangiopathy.