Recurrent Airway Swelling in a Patient With Lymphoproliferative Disorder: A Diagnostic Challenge Between Anaphylaxis and Acquired Angioedema.

Distinguishing between anaphylaxis and bradykinin-mediated angioedema can be difficult in the acute setting, particularly when airway compromise dominates the presentation. Recognition is crucial, as management strategies differ substantially. An 84-year-old woman presented to the Emergency Department in Preston with rapidly progressive swelling of the lips, tongue, and neck, accompanied by dysphagia and a hoarse voice. She had self-administered multiple doses of an adrenaline autoinjector before arrival. On examination, she was hemodynamically stable and afebrile, with marked tongue and floor-of-mouth edema but no urticaria or pruritus. Considering refractory anaphylaxis, she received intravenous dexamethasone, an adrenaline nebulizer, and an adrenaline infusion. ENT and ICU teams were involved; flexible nasendoscopy confirmed edema of the floor of the mouth and arytenoids, with mild epiglottic involvement but an adequate glottic opening. This episode followed several similar admissions since 2022, each previously treated as anaphylaxis with limited response to adrenaline. Further investigation revealed normal mast-cell tryptase (6.1 µg/L) and persistently low C4 (<0.03 g/L) with normal C3 (1.29 g/L), findings consistent with C1-esterase inhibitor (C1-INH) deficiency. Given her history of CD5-negative low-grade B-cell lymphoproliferative disorder, a diagnosis of acquired angioedema was made following multidisciplinary review, and treatment with icatibant was initiated. This case highlights the importance of considering bradykinin-mediated angioedema in patients with recurrent "refractory anaphylaxis." The absence of urticaria, normal tryptase, and low complement levels should prompt evaluation for C1-INH deficiency, allowing timely, targeted management and improved outcomes.