C32-03 Indirect Mucosal Contact-Induced Ofloxacin Anaphylaxis in a CiprofloxacinAllergic Patient

Introduction Fluoroquinolone-induced anaphylaxis is rare, and topical formulations are generally considered low-risk. Cross-reactivity within the class is reported but poorly characterized. Literature review revealed no prior reports of indirect mucosal exposure causing life-threatening anaphylaxis. We present the first known case highlighting this underrecognized risk. Case Presentation A 44-year-old female teacher with asthma and documented ciprofloxacin anaphylaxis developed acute dyspnea, wheezing, generalized pruritus, and perioral tingling minutes after a student applied ofloxacin ophthalmic drops, rubbed his eyes, and subsequently touched her eyes and mouth. No other medications, foods, or environmental exposures were identified. She initially received two intramuscular epinephrine doses (0.3 mg each) with transient improvement but experienced recurrence of symptoms. On arrival: BP 175/86 mmHg, HR 126 bpm, RR 33/min, SpO2 98% on room air; examination revealed diffuse expiratory wheezes. Labs were unremarkable except for lactate 5.2 mmol/L (post-epinephrine). Intensive care unit management included continuous epinephrine infusion, intravenous antihistamines, corticosteroids, H2 blockers, and nebulized bronchodilators, resulting in marked improvement within 24 hours and discharge after 48 hours. Discussion This case demonstrates that even minor indirect mucosal exposure to fluoroquinolones may potentially trigger life-threatening reactions in sensitized individuals. Potential mechanisms include IgE-mediated hypersensitivity or non-IgE mast cell activation (e.g., MRGPRX2). Fluoroquinolone cross-reactivity occurs in 2-5%, and topical-induced anaphylaxis is extremely rare. However, it has been previously reported. Clinicians should obtain detailed allergy histories, counsel patients regarding indirect exposures, and maintain a low threshold for epinephrine administration.