Aspirin or other nonsteroidal inflammatory agent exacerbated asthma

Aspirin-exacerbated respiratory disease (AERD) is an asthma phenotype with a prevalence that ranges from 2% to 25% of the asthma population. The 2% prevalence applies to patients with mild and 25% to severe, persistent asthma. COX-1-inhibiting nonsteroidal anti-inflammatory drugs, including aspirin, aggravate the preexisting upper and lower respiratory disease, sometimes in a life-threatening manner. The upper airway disease is characterized by an eosinophilic, hyperplastic rhinosinusitis with polyps. Eosinophilia, both peripheral and in the airways with Th2 inflammation, characterizes this disease. The role of allergic sensitivity in AERD is unclear, even though more than 30% of affected patients produce specific IgE to environmental allergens. Clinically, the respiratory symptoms are not usually associated with allergen exposure. The mechanism responsible for this phenotype is likely related to leukotriene (LT) metabolism because patients who are affected compared with patients who were aspirin tolerant, produce greater amounts of cysteinyl LTs. The synthesis of cysteinyl LTs is further increased after aspirin challenge and symptom exacerbation. Eosinophilia as well as a variety of other biologic markers, for example, Th2 cytokines, peripheral blood periostin, and LT enzymes and receptors, are associated with AERD both in the blood and in respiratory mucosa. These markers may help identify patients with AERD, but aspirin or other nonsteroidal anti-inflammatory drugs challenge is the primary means to confirm the diagnosis. A variety of single nucleotide polymorphisms and genes are associated with AERD, but the studies to date are limited to select populations and have not conclusively demonstrated a uniform genetic pattern in subjects with this disease. Treatment of AERD can be challenging because the nasal symptoms, including polyposis, are often refractory to both surgery and medical treatment, and the asthma can be difficult to control. Aspirin desensitization, followed by daily aspirin administration, can improve both upper and lower respiratory tract symptoms in up to 60% of individuals.