Aspirin-Exacerbated Respiratory Disease (AERD)
Aspirin-exacerbated respiratory disease (AERD), also known as Samter’s Triad, is a chronic medical condition that consists of three clinical features: asthma, sinus disease with recurrent nasal polyps, and sensitivity to aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) that inhibit an enzyme called cyclooxygenase-1. This sensitivity usually manifests as respiratory reactions that occur upon ingesting or inhaling an NSAID, though the exact cause of the reactions is not known. Approximately 9% of all adults with asthma and 30% of patients with asthma and nasal polyps have AERD. In general, AERD develops quite suddenly in adulthood, usually between the ages of 20 and 50, and there is no clearly understood trigger that causes the disease.
People with AERD usually have asthma, nasal congestion and recurrent nasal polyps, and their symptoms often do not respond to conventional treatments. Many have experienced chronic sinus infections and a loss of sense of smell is common.
The characteristic feature of AERD is that patients develop reactions to aspirin and other NSAIDs. These reactions classically involve both upper respiratory symptoms (increased nasal congestion, frontal headache or sinus pain, and sneezing) as well as lower respiratory symptoms (cough, wheezing, chest tightness), but they can also induce skin flushing, rash, abdominal pain and occasionally vomiting.
It has been noted that about 75% of all patients with AERD develop mild-to-moderate respiratory reactions when they drink alcohol. These reactions are not always specific to just one type of alcohol and often occur after consuming less than one glass of alcohol.
The diagnosis of AERD is a clinical one, meaning that there is no one specific test or blood result that alone can be used to diagnose the disease. The symptom triad of asthma plus nasal polyps plus respiratory reactions to NSAIDs is all that is needed for the diagnosis. However, for patients in whom their history of possible reaction to an NSAID is not clear, it is often helpful to do a formal aspirin challenge to confirm the diagnosis. This can be done either as an oral challenge, or as a combination of an intranasal and oral challenge, and the procedure is done in a hospital or clinic with an experienced doctor and medical team.
Additionally, people with AERD have large numbers of eosinophils in their nasal polyps and often have elevated levels of eosinophils in their blood. Eosinophils are a type of immune cell that is involved in inflammation. Though the presence of an elevated eosinophil level is not required as part of the diagnosis, it can be a helpful additional insight for these patients.
Treatment and Management
People with AERD who have not been desensitized to aspirin should avoid all NSAIDs in order to prevent reactions. However, even with the complete avoidance of NSAIDs, patients will continue to have symptoms of asthma, nasal congestion and recurrent polyps. Acetaminophen is usually safely tolerated at low doses (up to 500mg at a time).
Most patients with AERD will need to use daily medications to control their symptoms and often need to use daily inhaled corticosteroids for asthma. Intranasal steroid sprays or steroid sinus rinses can help to control the nasal symptoms, and nasal polyps can also be treated with occasional courses of oral steroids. Several non-steroid medications are also available, specifically medications that inhibit the production of leukotrienes (zileuton) or block the function of leukotrienes (montelukast and zafirlukast), and can help to treat some of the symptoms. Despite intensive medical therapy, the need for surgical removal of nasal polyps in AERD is very common, though unfortunately the rate of recurrence of nasal polyps after surgery is high.
Aspirin desensitization in order to initiate daily high-dose aspirin therapy can also be used as a steroid-sparing treatment in some patients. In patients with AERD, an aspirin desensitization procedure can be performed by administering gradually increasing doses of aspirin in a hospital or clinic that specializes in such treatment. The goal of aspirin desensitization is to have the patient begin long-term daily aspirin therapy, which in some patients can decrease the regrowth of nasal polyps and reduce the need for corticosteroid medications.
Newer injectable medications, called biologics, are now available for patients with moderate to severe asthma and for the treatment of nasal polyps. The medications mepolizumab, benralizumab, reslizumab and dupilumab are indicated in the treatment of moderate to severe eosinophilic asthma, and dupilumab also has indications in the treatment oral steroid dependent asthma and chronic rhinosinusitis with nasal polyps. Many patients with Aspirin-exacerbated respiratory disease (AERD) benefit from the addition of these specialized medications to their treatment.
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