A Rare Case of Idiopathic Angioedema Associated With Amlodipine Use

Angioedema is a self-limited, non-pitting edema of subcutaneous or submucosal tissues often affecting the face, lips, oral cavity, and airway. It may be histamine or bradykinin-mediated and is most commonly triggered by allergic reactions, medications, or systemic conditions. Drug-induced angioedema is frequently associated with angiotensin-converting enzyme (ACE) inhibitors, whereas calcium channel blockers (CCBs) like amlodipine are rarely implicated. This case report describes a rare case of recurrent angioedema in a hypertensive patient, ultimately attributed to amlodipine, and underscores the importance of a thorough evaluation and medication review in persistent idiopathic angioedema. A 63-year-old male patient with a history of hypertension, hyperlipidemia, and obstructive sleep apnea presented with recurrent episodes of tongue swelling and dyspnea beginning one week after the initiation of ramipril and amlodipine. Ramipril was initially suspected and discontinued, yet symptoms persisted despite multiple antihypertensive regimen changes and negative evaluations for hereditary angioedema and carcinoid syndrome. Allergy testing indicated idiopathic histaminergic angioedema, and a variety of symptomatic treatments provided limited relief. Ultimately, discontinuation of amlodipine in November 2024 resulted in the complete resolution of angioedema, with no recurrence noted over the next few months of subsequent follow-up. The Naranjo Algorithm is a structured, 10-question tool used to determine the likelihood that an adverse drug reaction (ADR) is actually caused by a specific medication. It assesses factors such as the timing of the reaction, alternative causes, drug levels, and response to dechallenge or rechallenge, which determines if an ADR is definite, probable, possible, or doubtful. Retrospective assessment using this algorithm yielded a score of 7, indicating a probable ADR. This case highlights amlodipine as a rare but important cause of drug-induced angioedema. It emphasizes the need for careful medication review in patients with unexplained, recurrent angioedema and the benefit of considering less common etiologies when standard evaluations are inconclusive. Prompt recognition and discontinuation of the offending agent can result in full resolution and prevent unnecessary morbidity.