Digital vasculitis following allergic desensitization treatment.

Systemic necrotizing vasculitis or a polyarteritis nodosa-like clinical presentation, is an unusual complication of immunotherapy (hyposensitization therapy). We describe a patient who developed features of vasculitis several years after beginning hyposensitization treatment for allergic rhinitis. In the 7 months preceding the onset of the vasculitis he experienced 4 episodes of anaphylaxis immediately after receiving desensitization injections. The vasculitis was characterized by the abrupt onset of pain and discoloration of the middle 3 digits of his right hand. Cyanosis and small areas of frank necrosis of these digits were present. Erythrocyte sedimentation rate and C-reactive protein were elevated and total serum complement was decreased. The development of digital vasculitis following hyposensitization is clearly illustrated in this patient.