An Unexpected Case of Cutaneous Vasculitis Following Zoledronic Acid Infusion.

We report a case of isolated cutaneous small vessel vasculitis (SVV) occurring after zoledronic acid (Zol) infusion in a 58-year-old postmenopausal woman with a history of sleeve gastrectomy. This was the patient's first exposure to a bisphosphonate medication. Within minutes of the Zol infusion, she developed an episode of diffuse watery diarrhea. Although the diarrheal symptoms resolved quickly, she experienced nonsteroidal anti-inflammatory drug-responsive generalized myalgias and skin tenderness in her abdomen and extremities within a few hours. These symptoms progressed in severity over the next 5 days, and she developed nonblanching, palpable purpura extending from the ankles to the knees. Prior to Zol, labs showed sufficient 25-hydroxyvitamin D and calcium as well as normal renal and liver function. On day 10, laboratory tests revealed aspartate transaminase twice and alanine transaminase thrice the upper limit of normal. The patient was diagnosed with cutaneous SVV, with a timeline highly suggestive of an idiosyncratic reaction to Zol. She was successfully treated with a prednisone taper. No prior cases of Zol-induced cutaneous vasculitis have been reported, although there are a handful of reported cases of giant cell arteritis and urticarial vasculitis after bisphosphonate therapy. Clinicians should be aware that isolated cutaneous SVV may be a rare complication of Zol.