Zoster after Cyclophosphamide for Systemic Lupus Erythematosus or Vasculitis: Incidence, Risk Factors, and Effect of Antiviral Prophylaxis.

The incidence of zoster is high in systemic vasculitis and in patients with SLE exposed to intravenous CYC. CYC may favor postherpetic neuralgia. Prophylaxis by VCV should be considered, particularly in cases of lymphopenia < 500/µl at CYC initiation and during the year after.