Acquired angioedema late in the course of nivolumab treatment.

Rare reports of angioedema associated with immune checkpoint inhibitor (ICI) treatment have previously been described. The exact mechanism of these phenomena is unknown, but bradykinin release leading to increased vascular permeability might be involved. Clinicians, pharmacists, and patients should be aware of this rare side effect of ICIs as it can be life-threatening when involving the respiratory tract and causing impending airway obstruction.