THU449 An Unexpected Case Of Cutaneous Leukocytoclastic Vasculitis Following Zoledronic Acid Infusion
Authors: Zahedi Bita , Wallace Zachary S , Cote Maya McEwen , Yu Elaine Wei-Yin 
Published: October 2023

Disclosure: B. Zahedi: None. Z.S. Wallace: None. M.M. Cote: None. E.W. Yu: Grant Recipient; Self; Amgen Inc.

Background: Zoledronic acid is a potent amino-bisphosphonate frequently used in the treatment of osteoporosis. We report a case of small-vessel vasculitis with cutaneous manifestations occurring after zoledronic acid infusion, previously not reported in the literature. Clinical case: A 58-year old woman with a history of sleeve gastrectomy 1.5 years prior was treated for bone protection with an intravenous infusion of zoledronic acid (Zol) 5mg. This was the patient’s first exposure to a bisphosphonate medication. Within minutes of the infusion, she developed a single episode of diffuse watery diarrhea. Although GI symptoms resolved quickly, within a few hours she experienced generalized myalgias and skin tenderness in her abdomen and extremities, for which she took NSAIDs. These symptoms progressed in severity over the next 3-5 days, manifesting as bilateral hand and lower extremity edema and erythema; no fever/chills/sweats, mucocutaneous ulcers, or urinary symptoms were present. By Day 5, she developed palpable purpura without blanching above the ankles and extending to the knees. By Day 7, prednisone 60mg was started. Prior to Zol, labs showed sufficient 25-hydroxyvitamin D, normal calcium, renal and liver function. On Days 10 and 14, labs revealed AST and ALT, twice and thrice the upper limit of normal respectively. Other notable labs included normal UA, Ca, WBC, eGFR, nonelevated ESR/CRP, and a negative work up for an underlying infectious, inflammatory, ANCA-associated, hypocomplementemic or autoimmune process. Cutaneous findings resolved within 3 weeks of Zol, and transaminitis and edema resolved by week 4. In the setting of a negative lab workup and typical palpable purpura, the patient was diagnosed with leukocytoclastic cutaneous vasculitis (LCV), likely induced by Zol (Naranjo score of 5 consistent with probable adverse drug reaction). Although IgA-mediated Henoch-Schonlein Purpura (HSP) cannot be definitively ruled out in absence of a skin biopsy, the patient did not exhibit other clinical features of HSP, and the timeline is highly suggestive of an idiosyncratic drug reaction whereby Zol acted as a hapton to stimulate an immunologic vasculitis response. Up to 50% of patients with LCV have systemic involvement (renal, GI, pulmonary, cardiac or CNS). Cutaneous LCV usually carries a favorable prognosis after treatment with glucocorticoids. On review of the literature, no prior cases of bisphosphonate-induced LCV have been reported, although there are few cases of giant cell arteritis, uveitis and urticarial vasculitis with bisphosphonate therapy. Conclusions: This is the first case demonstrating cutaneous manifestations consistent with leukocytoclastic vasculitis due to zoledronic acid infusion, which was successfully managed with NSAIDs and glucocorticoids. Clinicians should be aware that LCV may be a rare hypersensitivity complication of Zol.

Presentation: Thursday, June 15, 2023