Aspirin-exacerbated respiratory disease (AERD) refers to the triad of asthma, chronic rhinosinusitis with nasal polyps, and intolerance of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). It is also commonly called NSAID-exacerbated respiratory disease (NERD/N-ERD), and historically aspirin-induced asthma and Samter's Triad. While NSAID intolerance is a defining feature of AERD, simple avoidance does not prevent the onset, development or perennial nature of the disease. The symptoms of NSAID-induced respiratory reactions in this syndrome are hypersensitivity reactions rather than the common true allergic reactions that trigger other allergen-induced asthma, rhinitis, or hives. AERD is not considered an autoimmune disease, but rather a chronic immune dysregulation of as yet unknown origin. EAACI/WHO classifies the syndrome as one of five types of NSAID hypersensitivity. Signs and symptoms AERD affects an estimated 0.3–0.9% of the general population, including around 7% of all asthmatics, about 14% of adults with severe asthma, and ~5-10% of patients with adult onset asthma. AERD is uncommon among children, with around 6% of patients, predominantly female, reporting disease onset during childhood. It is more prevalent among women by up to a 2:1 margin, usually begins in the patients twenties to forties, with mean age of onset around 35. AERD patients may not have any allergies, though allergies are significantly more common in AERD patients than the general population. While disease progression varies, most commonly the first symptom is rhinitis (inflammation or irritation of the nasal mucosa), which may manifest as sneezing, runny nose, or congestion. The disorder typically progresses to asthma, then nasal polyposis, with aspirin sensitivity coming last. Hyposmia or anosmia—reduction or loss of the ability to smell—are reported in more than 90% of patients, as inflammation within the nose and sinuses likely reaches the olfactory receptors. Reactions to NSAIDs range in severity and expression. Onset is usually relatively rapid, with a mean time of around one hour after ingestion, though reactions as late as three hours have been reported. Respiratory reactions are essentially universal, with bronchoconstriction occurring in close to 90% of patients and nasal congestion and rhinorrhea occurring in more than 40%. Other symptoms include urticaria (hives), flushing, angioedema and hypotension. Gastrointestinal reactions have also been reported in a subset of patients, and may be difficult to treat. Factors that affect reaction severity include NSAID dosage, underlying asthma control, leukotriene modifier usage and the state of the patient's nasal polyps. In addition to aspirin, patients also react