Aspirin triggers dangerous asthma attacks in roughly one in ten adults with asthma, a condition now called aspirin-exacerbated respiratory disease, or AERD. This is not a typical drug allergy. It is a distinct inflammatory syndrome that reshapes the airways and sinuses, and it demands specific diagnosis and management strategies that differ from ordinary asthma care. The story of aspirin and asthma goes well beyond “avoid the pill,” touching on how the body produces inflammatory chemicals, which painkillers are safe substitutes, and why some patients deliberately take aspirin as treatment.
What AERD Looks Like
AERD was historically called Samter’s triad because it involves three overlapping problems: asthma, nasal polyps, and intolerance to aspirin or similar painkillers.1PubMed Central. Samter’s Triad: State of the Art The condition usually shows up in adulthood, often in the twenties or thirties, and begins with persistent nasal congestion and loss of smell before the aspirin sensitivity becomes apparent. Common symptoms include nasal congestion, runny nose, sneezing, loss of smell, and sinus opacification, along with lower airway symptoms like wheezing and chest tightness that worsen over time.2Family Medicine & Primary Care Review. Samter’s Triad: pathogenesis, clinical picture, diagnosis, comparison of biological and surgical treatment and the role of aspirin desensitisation It tends to be more severe and harder to manage than chronic sinus disease without aspirin sensitivity.3PubMed. The Role of Surgery in Management of Samter’s Triad: A Systematic Review
Within minutes to a couple of hours after taking aspirin, a person with AERD can experience a dramatic flare: sudden nasal congestion, flushing, eye watering, and bronchospasm that drops lung function sharply. It is not a mild inconvenience. Without prompt treatment, this reaction can be life-threatening. What makes AERD tricky is that many people do not realize they have it until that first bad reaction, because the underlying sinus disease and asthma are already present and often attributed to other causes.
How Common It Is
A meta-analysis using both oral provocation tests and patient-reported histories found that about 9% of adults with asthma have AERD.4PubMed. NSAID-exacerbated respiratory disease: a meta-analysis evaluating prevalence, mean provocative dose of aspirin and increased asthma morbidity That figure rises steeply in people with severe asthma and severe chronic sinus disease with nasal polyps, where AERD is heavily overrepresented.5PubMed Central. Aspirin-exacerbated respiratory disease: Prevalence, diagnosis, treatment, and considerations for the future So while 9% is already a meaningful minority of asthmatics, the real clinical impact concentrates in the patients who are already the sickest and hardest to treat.
Why Aspirin Causes This Reaction
The mechanism is not an immune-system allergic response in the traditional sense, which is why specialists avoid calling it an “aspirin allergy.” Instead, it is a biochemical imbalance. Aspirin blocks an enzyme called COX-1, which normally helps produce a molecule called prostaglandin E2. In most people, losing some prostaglandin E2 is no big deal. But in people with AERD, prostaglandin E2 acts as an important brake on inflammation in the airways. When aspirin removes that brake, the body’s leukotriene pathway surges.6PubMed Central. Aspirin-exacerbated asthma
Leukotrienes are potent inflammatory molecules that tighten the airways, attract inflammatory cells, and increase mucus production. In AERD, the overproduction of a specific type called cysteinyl leukotrienes is a hallmark of the disease.7Blood. Cysteinyl leukotriene overproduction in aspirin-exacerbated respiratory disease is driven by platelet-adherent leukocytes These leukotrienes are already elevated at baseline in AERD patients, even before they take aspirin. An aspirin challenge then drives them sharply higher.8Allergology International. Mechanisms of aspirin-sensitive asthma Bronchial biopsies have shown that the enzyme responsible for manufacturing cysteinyl leukotrienes is overexpressed in the airways of people with AERD, and aspirin challenge floods the airway fluid with these molecules at levels far beyond what aspirin-tolerant asthmatics produce.9The Journal of Clinical Investigation. Overexpression of leukotriene C4 synthase in bronchial biopsies from patients with aspirin-intolerant asthma
Mast cells and eosinophils, two types of immune cells involved in inflammation, are heavily activated in AERD tissue and play central roles in driving these effects.10PubMed Central. Eosinophils and Mast Cells in Aspirin-Exacerbated Respiratory Disease Eosinophils in AERD also produce abnormally high amounts of prostaglandin D2, another inflammatory mediator, adding fuel to the airway inflammation.11PubMed Central. Eosinophil production of PGD 2 in Aspirin-Exacerbated Respiratory Disease
Other Painkillers That Cause the Same Problem
Because the reaction is driven by COX-1 inhibition rather than by something unique to aspirin’s chemical structure, other painkillers that strongly block COX-1 trigger the same response. Ibuprofen, naproxen, indomethacin, and ketoprofen all cross-react in people with AERD.12PubMed. Use of nonsteroidal anti-inflammatory drugs in patients with aspirin hypersensitivity: safety of cyclo-oxygenase-2 inhibitors If you have AERD, you cannot simply swap aspirin for ibuprofen; the whole class of traditional NSAIDs is off the table.
Acetaminophen (paracetamol) and selective COX-2 inhibitors like celecoxib are considered safer alternatives because they spare COX-1 at normal doses. However, they are not universally safe. One study found that about a third of AERD patients cross-reacted to acetaminophen.13PubMed Central. Cross-reactivity to Acetaminophen and Celecoxib According to the Type of Nonsteroidal Anti-inflammatory Drug Hypersensitivity Across patients with various types of NSAID hypersensitivity, about 16% reacted to at least one of the “safer” alternatives, including paracetamol, meloxicam, or nimesulide.14PubMed Central. Tolerability to paracetamol and preferential COX-2 inhibitors in patients with cross-reactive nonsteroidal anti-inflammatory drugs hypersensitivity The practical takeaway: if you know you have AERD, the safest approach is to test any new painkiller under medical supervision in a clinic equipped to handle a reaction, rather than assuming it will be fine.
How AERD Is Diagnosed
There is no simple blood test that confirms AERD. The gold standard is an aspirin provocation test, where you are given escalating doses of aspirin under close medical observation to see whether a reaction occurs. This can be done by mouth, through the nose, or by inhalation. European guidelines describe standardized protocols for all three routes, along with rules for which medications to stop beforehand and how to interpret results.15PubMed. EAACI/GA2LEN guideline: aspirin provocation tests for diagnosis of aspirin hypersensitivity
The oral test is the most sensitive but also carries the highest risk of triggering a full systemic reaction. Nasal and bronchial challenge tests are safer and faster alternatives, though they are slightly less sensitive. When respiratory tests come back negative but suspicion remains high, an oral challenge should still be performed before ruling out the diagnosis.16Current Treatment Options in Allergy. Respiratory Exposure Tests in Aspirin Exacerbated Respiratory Disease A recent study of intranasal aspirin challenge found that a cumulative dose of 70 mg achieved the best diagnostic accuracy, around 91%, and that nasal congestion and runny nose were the most prominent symptoms during testing. Importantly, fewer than 5% of participants experienced acute worsening of their asthma during the nasal challenge, making it a reasonably well-tolerated option.17PubMed. Intranasal Aspirin Challenge for Diagnosis of Aspirin-Exacerbated Respiratory Disease: Symptom Score Criteria and Optimal Dosage
Biomarkers That Point Toward AERD
While provocation testing remains the diagnostic standard, researchers have been working to find laboratory markers that could flag AERD without deliberately triggering a reaction. The most studied is urinary leukotriene E4, a breakdown product of those cysteinyl leukotrienes that are overproduced in AERD. It can be measured from a urine sample and reflects total body leukotriene production.18PubMed. Urinary Leukotriene E(4) as a Biomarker of Exposure, Susceptibility, and Risk in Asthma: An Update
A systematic review found that urinary leukotriene E4 has moderate accuracy for identifying aspirin intolerance in asthma patients, with sensitivity and specificity values varying depending on the measurement technique used. Depending on the assay, sensitivity ranged from about 55% to 81%, with specificity between about 77% and 82%.19PubMed. Urinary Leukotriene E4 to Determine Aspirin Intolerance in Asthma: A Systematic Review and Meta-Analysis Those numbers are useful for screening but not sharp enough to replace a provocation test on their own. Combining urinary leukotriene E4 with blood eosinophil counts improves the picture: asthmatics with both high urinary leukotriene E4 and high blood eosinophils were about seven times more likely to have AERD than aspirin-tolerant asthmatics.20PubMed Central. The utility of biomarkers in diagnosis of aspirin exacerbated respiratory disease
Aspirin Desensitization as Treatment
Here is the counterintuitive part of the aspirin-and-asthma story: the same drug that causes dangerous reactions can become a treatment. Aspirin desensitization involves giving gradually increasing doses of aspirin under medical supervision until the patient tolerates a full therapeutic dose, then maintaining daily aspirin use indefinitely. The idea is that continuous exposure resets the inflammatory response over time.
Long-term follow-up data support this approach. In a study tracking AERD patients on continuous daily aspirin therapy for over a decade, roughly 62% stayed on the treatment, and among those who did, sense of smell, asthma scores, sinus symptoms, and allergic rhinitis scores all improved significantly. About 68% of patients remaining on aspirin avoided further sinus surgery, and nearly 85% reported that aspirin therapy improved their airway disease and quality of life.21PubMed. Long-term Clinical Outcomes of Aspirin Desensitization With Continuous Daily Aspirin Therapy in Aspirin-exacerbated Respiratory Disease A separate exploratory study found that after 18 months of desensitization, patients with poorly controlled asthma saw their lung function improve substantially, their asthma control improved, and their medication burden was reduced.22PubMed. Long-term clinical effects of aspirin-desensitization therapy among patients with poorly controlled asthma and non-steroidal anti-inflammatory drug hypersensitivity: An exploratory study
The catch is that roughly a third of patients discontinue aspirin over time, often because of gastrointestinal side effects from taking a daily NSAID. And missing even a couple of days can mean losing the desensitized state, requiring the entire protocol to be restarted. It is a commitment, and it requires a good relationship between patient and physician to manage the side effects and ensure compliance.
Medications That Target Leukotrienes
Since leukotriene overproduction is central to AERD, drugs that block leukotrienes are a logical treatment option. Montelukast, a widely prescribed leukotriene receptor antagonist used in many asthma patients, provides meaningful but incomplete protection. In one study, 12 weeks of montelukast treatment reduced the decline in lung function during aspirin challenge from roughly 29% to about 10%. However, 30% of patients still had a clinically significant reaction despite the medication.23Allergy, Asthma & Immunology Research. Protection of leukotriene receptor antagonist against aspirin-induced bronchospasm in asthmatics Montelukast blocks leukotriene receptors but does not stop leukotriene production, so it only partially dampens the inflammatory surge.
Zileuton takes a different approach by blocking the enzyme that makes leukotrienes in the first place. For AERD patients whose sinus disease is not adequately controlled by standard therapy including montelukast, switching to zileuton has shown promise. In one long-term study with an average treatment duration of six years, patients on zileuton needed significantly fewer sinus surgeries compared to their pre-zileuton rate. The reduction in surgeries was substantial and statistically significant, though improvements in symptom questionnaire scores trended positive without reaching statistical significance.24PubMed. Long-term role of zileuton in the treatment of chronic rhinosinusitis in aspirin exacerbated respiratory disease A separate study confirmed that zileuton may be more useful for reducing the need for surgery than for improving day-to-day sinus symptom scores.25PubMed Central. Effect of Zileuton Treatment on Sinonasal Quality of Life in Patients with Aspirin-Exacerbated Respiratory Disease Zileuton requires liver function monitoring and is taken multiple times daily, which limits its convenience, but for patients facing repeated sinus surgeries it can be a meaningful addition.
The Low-Salicylate Diet
Many foods contain natural salicylates, which are chemically related to aspirin. Some researchers have tested whether reducing dietary salicylate intake helps AERD patients. A randomized crossover trial found that one week on a low-salicylate diet led to a statistically significant reduction in nasal symptoms compared to baseline, whereas a high-salicylate diet did not.26PubMed Central. Effect of low salicylate diet on clinical and inflammatory markers in patients with aspirin exacerbated respiratory disease – a randomized crossover trial A separate multicenter randomized trial reported significant improvements in both upper and lower airway symptoms when AERD patients followed a low-salicylate diet compared to their regular diet, with statistically meaningful improvements across sinus symptom scores, asthma control, and endoscopic findings.27PubMed. A novel treatment adjunct for aspirin exacerbated respiratory disease: the low-salicylate diet: a multicenter randomized control crossover trial
These are small trials, and implementing a low-salicylate diet is not simple. Salicylates appear in a wide range of fruits, vegetables, spices, and beverages, so the diet is restrictive and difficult to sustain long-term. Still, for patients who are struggling despite medications and surgery, it represents an additional lever to pull. Researchers frame it as a treatment add-on rather than a standalone strategy.
Aspirin Desensitization in Pregnancy
A less obvious intersection of aspirin and asthma arises during pregnancy. Low-dose aspirin is widely recommended to prevent preeclampsia and other placental complications in high-risk pregnancies. But women who have AERD cannot simply start taking aspirin. For these patients, aspirin desensitization before or during pregnancy has been described as a valuable option, allowing them to safely begin daily low-dose aspirin to protect against pregnancy complications that would otherwise go unaddressed.28PubMed Central. Aspirin Desensitization: Implications for Acetylsalicylic Acid-Sensitive Pregnant Women This is a niche situation, but it highlights how AERD can create ripple effects into areas of medicine that seem entirely unrelated to asthma.
Living With AERD and the Burden of Lost Smell
AERD does not just affect breathing. The nasal polyps that define the condition frequently destroy the sense of smell, and that loss carries psychological weight that is easy to underestimate. In a study of AERD patients, 85% reported diminished smell or taste, and 30% rated their smell loss as “as bad as it can be.” The severity of smell loss was significantly associated with psychological distress and worse general health scores, even after accounting for how well their asthma was controlled. Patients with diminished smell reported that they could not identify spoiled food, did not enjoy eating, felt unsafe in their homes, and had encountered dangerous situations because they could not smell smoke or gas.29PubMed Central. Loss of smell in patients with aspirin-exacerbated respiratory disease impacts mental health and quality of life
Interestingly, a separate study comparing AERD patients to asthma-only patients found that AERD patients actually reported lower depression scores, better asthma-related quality of life, and perceived their asthma as less severe.30PubMed Central. Depression symptoms and quality of life among individuals with aspirin-exacerbated respiratory disease That seems paradoxical given the objective severity of AERD, but it may reflect the fact that patients with a clear diagnosis and a specific management plan feel more in control of their disease than patients with poorly explained, poorly controlled asthma. Having a name for your condition and a treatment roadmap can itself be a form of psychological relief, even when the condition is objectively worse on paper.