Angioedema is a transient, localized swelling caused by two distinct mechanisms, mediated by
histamine and
bradykinin, respectively, although a proportion of cases remain idiopathic. Studies that characterize undifferentiated
angioedema presenting in emergency departments (EDs) are limited. This study investigates the presentation patterns of undifferentiated
angioedema in the ED based on the presumed mechanism of swelling. Medical records from all ED visits to two tertiary care hospitals from July 2007 to March 2012 were electronically reviewed. Records with documented visible swelling on general inspection and/or fiberoptic laryngoscopy and a diagnostic code for
anaphylactic shock,
angioneurotic edema,
allergy unspecified, defects in the
complement system, or unspecified
drug adverse effects were included. Demographic, clinical, and outcome data were collected via a standardized form. Data were analyzed descriptively, including frequencies and percentages for categorical data and means and SDs for continuous data. Predictors for admission were identified using multivariate logistic regression models. ED records from 527 visits for
angioedema by 455 patients were included in the study. Annual rate of
angioedema was 1 per 1000 ED visits.
Urticaria was associated with peripheral (p = 0.008) and lip
angioedema (p = 0.001), and the absence of
urticaria correlated with tongue
angioedema (p = 0.001) and trended toward correlation with pharyngeal
angioedema (p = 0.056). Significant predictors of admission included nonsteroidal anti-inflammatory
drug-induced
angioedema (odds ratio [OR], 15.3),
epinephrine treatment (OR, 8.34),
hypotension (OR, 15.7), multiple-site
angioedema (OR, 4.25), and pharyngeal (OR, 1.23) and tongue
angioedema (OR, 4.62). Concomitant
urticaria was associated with a significant longer stay in the ED (p < 0.001). The presence of
urticaria correlated with the location of
angioedema, need for
airway management, length of ED visit, and recurrence. A detailed
drug and family history, screening blood work for
C1 esterase inhibitor deficiency when indicated, and prompt management of
angioedema based on presumed mechanism of swelling are crucial steps in managing undifferentiated
angioedema in ED.