LAUSR

Dear Editor, A 71-years-old woman, a known case of osteoporosis, T12 vertebral collapse, pulmonary Koch's, hypertension, hyperuricemia, and diabetes presented to the emergency department with reddish itchy lesions over face, trunk, bilateral upper limbs, and lower limbs for the past 3 days. These lesions started from the trunk followed by involvement of extremities, and face within few hours. Lesions appeared 1 day after taking zoledronate intravenous injection for osteoporosis. There was no history of swelling of lips, eyelids, breathlessness, and pain in the abdomen. There was no history of fever, joint pain, cola-colored urine, difficulty in getting up from squatting position, combing hair, and myalgia. Treatment history includes telmisartan, febuxostat, metformin for the past 7–8 years, and antitubercular (first line) drugs for the past 1 month. For cutaneous lesions, the patient had taken antihistamines for 3 days with minimal relief. On examination, there were multiple erythematous, edematous papules and plaques with few lesions showing purpura, nonscaly, partially blanchable to nonblanchable, nontender, varying in size from 0.5 0.5 cm to 6 6 cm over face, trunk (Figure S1), buttocks (Figure 1A), bilateral upper and lower limbs (Figure S2), palms, and soles. Scalp and mucosae were normal. There was no evidence of angioedema, lymphadenopathy, hepatosplenomegaly, and muscle tenderness. A skin biopsy from urticarial plaque showed moderately dense perivascular and interstitial infiltrate of neutrophils and some eosinophils accompanied by nuclear dust and extravasation of red blood cells in the superficial and mid dermis. The histological features were suggestive of small vessel vasculitis (Figure 1B). Naranjo adverse drug reaction probability score was five suggesting probable association of rash with zoledronate. There was mild neutrophilic leucocytosis and mildy elevated lactate dehydrogenase level. Other blood investigations (ANA, CPK, urine routine microscopy, C3, and C4) were unremarkable. Based on temporal association, clinical and histopathological findings, and Naranjo score, the diagnosis of zoledronate induced urticarial vasculitis was made. It was advised to stop zoledronate and oral antihistamines and topical steroid were prescribed. The rest of the medications were continued. Lesions completely resolved within 1 week of treatment with post-inflammatory hyperpigmentation. Zoledronate is a bisphosphonate used for the prevention and treatment of osteoporosis. It inhibits the proliferation of osteoclasts and induces their apoptosis leading to a decrease in bone resorption. Common systemic side-effects caused by bisphosphonates include nausea, renal toxicity, osteonecrosis of jaw, nonspecific conjunctivitis, and atrial fibrillation. Cutaneous adverse effects due to bisphosphonates are quite rare and include urticaria, lichen planus (alendronate), symmetrical drugrelated intertriginous and flexural exanthema (zoledronate), fever with rash (zoledronate), spongiotic dermatitis (alendronate), interface dermatitis (zoledronate), figurate erythema (alendronate), and vasculitis (risedronate). Vasculitis is inflammation of the vessel wall. It can be due to various causes like drugs, infections, malignancy, connective tissue disorders, and inflammatory dermatoses or may be idiopathic. We report a rare case of urticarial vasculitis secondary to zoledronate based on