Churg-Strauss syndrome: diagnostic difficulties and pathogenesis.

A 52-year-old woman with a history of chronic obstructive pulmonary disease presented with symmetrical polyarthritis involving her metacarpophalangeal and proximal interphalangeal joints, knees, ankles, and hips and with a purpuric rash involving her lower extremities. She had a history of recurrent episodes of purulent otitis often associated with myalgias and arthralgias. Laboratory studies at presentation included leukocytosis with 16% eosinophils, an elevated rheumatoid factor titer, and an elevated antineutrophil cytoplasmic antibody titer. Cultures from the right ear canal grew. Skin biopsy revealed leukocytoclastic vasculitis with pericapillary eosinophils. The patient was treated with prednisone and then with azathioprine after the rash relapsed during the tapering of prednisone. Four months after her initial presentation, she developed bilateral foot drop. A sural nerve biopsy revealed vasa nervosum vasculitis. The diagnosis of Churg-Strauss syndrome was established, and she was treated with an increased dose of azathioprine and a slowly tapering prednisone regimen. This case report suggests that patients with Churg-Strauss syndrome can present with a syndrome suggesting rheumatoid arthritis. In this particular patient, recurrent staphylococcal infections may have triggered the vasculitic process.