A Case of IgA Vasculitis During Nivolumab Therapy for Renal Cell Carcinoma.

A 50-year-old Japanese woman presented with a 4-day history of multiple purpura on her extremities and myalgia. She had been receiving nivolumab therapy for stage IV renal cell carcinoma for 18 months. Nivolumab was temporarily discontinued due to liver dysfunction and resumed 3 months before. Biopsy specimen revealed leukocytoclastic vasculitis, and direct immunofluorescence showed deposition of IgA and C3 in the vessel walls of the upper dermis. Based on these findings, a diagnosis of IgA vasculitis was made. She was treated with  20 mg/day of  oral prednisolone, which resulted in the complete disappearance of purpura and myalgia. Although the patient needed temporary cessation of nivolumab therapy, she experienced no recurrence of purpura or myalgia, and the dose of prednisolone was gradually tapered to 5 mg/day. Although nivolumab can lead to various immune-related adverse events, vasculitis is rare. To the best of our knowledge, this is the second case of IgA vasculitis during nivolumab therapy.