Aspirin or Nonsteroidal Anti-inflammatory Drug-Exacerbated Chronic Rhinosinusitis

Aspirin (ASA)-exacerbated respiratory disease (AERD) is characterized by upper airway congestion due to eosinophilic inflammation of the nasal and sinus membranes and nasal polyposis, associated with increased leukotriene production that is further accentuated by ASA or other nonsteroidal anti-inflammatory drug (NSAID) ingestion. It occurs in 5% to 10% of subjects with chronic rhinosinusitis (CRS) and in 15% to 40% of those with nasal polyposis. Although AERD with CRS is usually associated with asthma, this is not always the case. The eosinophilic airway inflammation and symptoms precede clinical reactions to ASA or other NSAIDs, but ultimately affected subjects experience worsening of symptoms with ingestion of ASA/NSAIDs. The endotypic mechanism for this worsening is related to a chronic increase in leukotriene and a decrease in prostaglandin production, particularly prostaglandin E2, that is further aggravated by the inhibition of cycloxgenase I. IgE does not likely play a role in the pathogenesis of the disease although nasal and sinus staphylococcal infection increases local IgE level and may increase total IgE and specific IgE levels. Genetic studies suggest that multiple genes may be involved, but the genetic abnormalities may differ in affected subjects from different ethnicities and candidate genes have not been confirmed in multiple studies. Genome-wide association studies have not been revealing. The phenotype is recognized by the mucosal inflammation and worsening of symptoms acutely with ASA/NSAID. There is clinical improvement with ASA desensitization followed by regular ingestion of ASA or other NSAIDs. Further understanding of this unique phenotype and endotype of CRS will likely improve the understanding of other eosinophilic airway diseases.