Incidence of aspirin hypersensitivity in patients with chronic rhinosinusitis and diagnostic value of urinary leukotriene E4

INTRODUCTION Chronic rhinosinusitis (CRS) with nasal polyposis (NP) may be associated with hypersensitivity to nonsteroidal anti-inflammatory drugs, representing a syndrome of aspirin-exacerbated respiratory disease (AERD). 
OBJECTIVES The aim of the study was to validate a simple measurement of urinary leukotriene E4 (uLTE4) excretion for the diagnosis of AERD in patients with CRS and indication for surgery. 
PATIENTS AND METHODS Subjects requiring functional endoscopic sinus surgery (FESS) were recruited from the Department of Otolaryngology (n = 24). Before surgery, a standard oral placebo-controlled aspirin challenge was performed to diagnose aspirin hypersensitivity. Urine samples were collected on the placebo day and both before and within 2 to 4 hours after aspirin challenge for uLTE4 measurement.
RESULTS All patients with CRS had sinusitis confirmed by computed tomography. Previous ear, nose, and throat surgery was performed in 70% of the patients, NP was present in 86%, and asthma was diagnosed in 62.5%. AERD was diagnosed in 8 subjects (7 women and 1 man). Five of those patients had bronchoconstriction. At baseline, median uLTE4 was 7.5-times higher in AERD subjects than in the remaining patients. It increased almost 6-fold following the challenge, while remained unchanged in patients without aspirin hypersensitivity. Pretest uLTE4 had a sensitivity of 87.5% and specificity of 93.75% to diagnose aspirin hypersensitivity in patients with CRS. After the challenge, the values improved to 100% sensitivity and 93% specificity.
CONCLUSIONS Among CRS subjects requiring FESS, as many as 33.3% may have AERD and respond to a small provocative dose of aspirin with bronchoconstriction and/or mucosal and skin edema. A simple and inexpensive measurement of uLTE4 can help diagnose AERD in patients with CRS with sensitivity of 87.5%, but its specificity is limited and depends on the arbitrary threshold of uLTE4.