Disseminated varicella-zoster virus infection with gastrointestinal prodromal symptoms during daratumumab therapy for relapsed and refractory multiple myeloma.

Varicella-zoster virus (VZV) reactivation is a recognized complication in patients with multiple myeloma, particularly during treatment-associated immunosuppression. Although disseminated VZV infection is uncommon, delayed diagnosis may result in life-threatening disease. We report a Japanese woman in her 70s with relapsed and refractory multiple myeloma who developed anorexia, vomiting, and fever before the appearance of disseminated vesicular eruptions during daratumumab-based therapy. Laboratory findings showed cytopenia, marked liver dysfunction, and hypogammaglobulinemia. Disseminated VZV infection was confirmed by antigen testing, and prompt intravenous acyclovir resulted in clinical recovery. This case highlights that disseminated VZV infection may initially present with gastrointestinal symptoms before characteristic skin lesions during anti-CD38-based therapy, representing an important diagnostic pitfall. Early recognition, prompt antiviral therapy, and consideration of antiviral prophylaxis may help reduce the risk of severe disease.