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Varenicline‐induced erosive stomatitis: First case report

We present a case of erosive stomatitis as a manifestation of hypersensitivity to varenicline. A 65-year-old man was referred to the dermatology department after presenting with small vesicles and erosions in the mucosa of the lower lip that, in a few days, spread throughout the oral cavity (Figure 1). The lesions started 20 days after he initiated varenicline treatment. The patient had a previous history of hypertension, hyperuricemia, and bladder carcinoma in remission, with no allergological history of interest, and daily medication of atorvastatin, dutasteride/ tamsulosin, allopurinol, and olmesartan/amlodipine. Laboratory tests showed mild leukocytosis, negative autoantibodies (antinuclear antibodies, anti-basement membrane antibody), negative polymerase chain reaction (PCR) for herpes virus and candida culture, and a normal immunoglobulin and complement study. He completed treatment with ciprofloxacin, valacyclovir, and fluconazole without improvement. Therefore, the dermatologists prescribed 30 mg of prednisone and removed from his treatment varenicline (1 mg tablet), olmesartan/amlodipine, and allopurinol (which he had been taking for years) with a complete resolution of symptoms. After 2 weeks, coinciding with the suspension of prednisone, and the reintroduction of varenicline and ciprofloxacin (for a urinary tract infection), he presented the same oral lesions as before. He stopped varenicline and started systemic corticosteroid therapy again, with complete recovery within 3 weeks. Then he reintroduced his usual treatment, except for varenicline without further relapses. Afterward, he was assessed by the allergology department. We performed a lymphocyte transformation test (LTT) with varenicline, levofloxacin, ciprofloxacin, and moxifloxacin, being only positive to varenicline, confirming a type IV hypersensitivity mechanism (Table 1). Subsequently, the patient tolerated an oral challenge test with ciprofloxacin.