Initial increase in the cryoglobulin level after rituximab therapy for type II cryoglobulinemia secondary to Waldenström macroglobulinemia does not indicate failure of response.

Type II (mixed) cryoglobulinemia is a systemic vasculitis that may affect many organs, including the skin, leading to ulcerations secondary to immune complex deposition. We report a patient who presented with a large necrotic ulcerative lesion on the right ankle secondary to type II cryoglobulinemic vasculitis due to Waldenström macroglobulinemia that was resistant to multiple modalities of therapy. Amputation to prevent further necrosis and infections was almost performed. Treatment with rituximab was initiated and the patient had a dramatic response. This case report highlights the effectiveness and prompt response to rituximab when used in patients with small vessel vasculitis and skin ulceration. We describe a rise in the cryoglobulin level that may occur initially after rituximab therapy. 2004 Wiley-Liss, Inc.