Disseminated herpes zoster mimicking rheumatoid vasculitis in a rheumatoid arthritis patient on etanercept.

Tumor necrosis factor-alpha (TNFalpha)-blocking agents are immunomodulating agents introduced for treatment of a variety of chronic inflammatory disease conditions. Adverse effects include an increased incidence of infections. Clinically, these infections often have atypical presentations that may hamper prompt diagnosis. In our report of a patient on etanercept therapy for rheumatoid arthritis, the correct diagnosis was delayed because disseminated herpes zoster was clinically mimicking vasculitis. Initially assuming rheumatoid vasculitis, immunosuppression was increased, resulting in worsening of skin lesions. Only an extended work-up, including a skin biopsy and viral cultures, established the correct diagnosis. Management of varicella zoster virus (VZV) infection primarily focuses on early initiation of antiviral therapy to control VZV replication. Therapy with intravenous acyclovir followed by oral valacyclovir allowed complete resolution of acute skin changes. In immunosuppressed patients, the possibility of infection with atypical presentation must always be kept in mind, and that this might mimic other disease conditions. Broad differential diagnosis and an extended diagnostic workup help in establishing the correct diagnosis. Copyright 2009 S. Karger AG, Basel.