Aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD), also called NSAID-exacerbated respiratory disease (N-ERD) or historically aspirin-induced asthma and Samter's triad, is a long-term disease defined by three simultaneous symptoms: asthma, chronic rhinosinusitis with nasal polyps, and intolerance of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). Compared to aspirin tolerant patients, AERD patients' asthma and nasal polyps are generally more severe. Reduction or loss of the ability to smell is extremely common, occurring in more than 90% of people with the disease. AERD most commonly begins in early- to mid-adulthood and has no known cure. While NSAID intolerance is a defining feature of AERD, avoidance of NSAIDs does not affect the onset, development or perennial nature of the disease.

The cause of the disease is a dysregulation of the arachidonic acid metabolic pathway and of various innate immune cells, though the initial cause of this dysregulation is currently unknown. This dysregulation leads to an imbalance of immune related molecules, including an overproduction of inflammatory compounds such as leukotriene E4 and an underproduction of anti-inflammatory mediators such as prostaglandin E2. This imbalance, among other factors, leads to chronic inflammation of the respiratory tract.

A history of respiratory reactions to aspirin or others NSAIDs is sufficient to diagnose AERD in a patient that has both asthma and nasal polyps. However, diagnosis can be challenging during disease onset, as symptoms do not usually begin all at once.