Aspirin-Exacerbated Respiratory Disease
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Direct answer
The triad of asthma, chronic rhinosinusitis with nasal polyps and respiratory reactions to NSAIDs — aspirin-exacerbated respiratory disease (AERD, Samter's triad) — is not an allergy at all: COX-1 inhibition diverts arachidonic acid into the 5-lipoxygenase pathway, flooding patients with cysteinyl leukotrienes whose hallmark is high urinary LTE4. Adult-onset, usually non-atopic patients progress through polyp regrowth and steroid dependence, and management combines leukotriene modulation, biologics such as dupilumab, and — in selected cases — aspirin desensitisation carried out only in a monitored setting with controlled asthma. That mechanism-and-management pairing is a recurring NEET-PG Medicine theme.
What you must remember
- Triad: asthma + chronic rhinosinusitis with nasal polyps + NSAID hypersensitivity; adults in their thirties, non-atopic, with a modest female predominance.
- Not IgE-mediated: reactions follow COX-1 inhibition in any NSAID (aspirin, ibuprofen, naproxen), dose-dependent and pharmacological, not allergic.
- Mechanism: arachidonic acid shunted to the 5-lipoxygenase pathway; baseline and post-aspirin urinary LTE4 are markedly elevated.
- Typical reaction 30 minutes to 3 hours after ingestion: profuse rhinorrhoea, nasal congestion, flushing, conjunctival injection, bronchospasm — occasionally severe anaphylactoid events.
- COX-2 selective inhibitors (e.g. celecoxib) are generally tolerated under supervised challenge; paracetamol at moderate doses is usually safe.
- Aspirin desensitisation — ascending oral doses to a maintenance of typically 650 mg twice daily — reduces polyp regrowth, restores smell and cuts steroid courses in responders.
- Desensitisation prerequisites: controlled asthma (FEV1 above about 60–70% of predicted), monitored setting, and uninterrupted daily dosing afterwards, since missing more than a few days loses the desensitised state.
- Adjuncts: leukotriene receptor antagonists (montelukast) or the 5-lipoxygenase inhibitor zileuton; biologics (dupilumab, mepolizumab, omalizumab) now reduce polyp burden and steroid dependence.
- Every reaction involves every COX-1 inhibitor — there is no "safe ibuprofen" in this syndrome.
How to work through a typical case
A 38-year-old woman with no childhood atopy developed asthma at 30, then anosmia and bilateral nasal polyps requiring two endoscopic sinus operations in three years; last month, one ibuprofen tablet produced streaming nose, flushing and wheeze treated in the emergency department.
Step one: recognise the completed triad — adult-onset asthma plus recurrent polyps plus a classic reaction — and stop calling it "ibuprofen allergy" in the notes; the diagnosis is pharmacological intolerance shared by all COX-1 inhibitors. Step two: characterise the mediator phenotype — she likely has marked eosinophilia, high urinary LTE4, and steroid-dependent disease with rapid polyp regrowth, the AERD signature. Step three: secure the airway and nose first — optimise asthma control with inhaled corticosteroid-long-acting bronchodilator, initiate a leukotriene antagonist or zileuton, and plan polyp management (surgical clearance plus topical steroid irrigations) with biologics such as dupilumab where available and affordable. Step four: counsel on drug safety in concrete terms — no over-the-counter aspirin, ibuprofen, diclofenac, naproxen or ketorolac; paracetamol up to moderate doses for fever and pain; supervised celecoxib challenge if a COX-2 inhibitor is genuinely needed. Step five: discuss aspirin desensitisation once asthma is controlled and the nose is optimised — ascending doses over one to two days in a monitored unit, then lifelong twice-daily aspirin; the benefits (fewer polyp operations, smell regained, steroid reduction) apply only while the daily dose continues, and missed doses beyond a few days require repeat desensitisation.
Where students slip
First, answering "IgE-mediated aspirin allergy" — the exam explicitly wants the COX-1/leukotriene pharmacology. Second, permitting "occasional ibuprofen" or switching between NSAIDs: every COX-1 inhibitor cross-reacts, and only COX-2 selectivity or paracetamol escape the rule. Third, attempting desensitisation during an asthma exacerbation or with unstable baseline lung function — the contraindication examiners probe. Fourth, forgetting that desensitisation is a state maintained by daily dosing, not a one-time cure. Finally, missing the diagnosis in the "polyps returning after surgery" stem — recurrent polyposis in an adult asthmatic should trigger an explicit NSAID reaction history.
Frequently asked questions
What constitutes the Samter triad?
Asthma, chronic rhinosinusitis with nasal polyps, and respiratory reactions to aspirin and other NSAIDs — collectively aspirin-exacerbated respiratory disease.
Why do NSAIDs trigger reactions in AERD?
Inhibition of COX-1 diverts arachidonic acid to the 5-lipoxygenase pathway, generating excess cysteinyl leukotrienes that cause bronchospasm, rhinorrhoea and flushing; it is pharmacological, not IgE-mediated.
Which analgesics are generally safe in AERD?
Paracetamol at moderate doses and, after supervised challenge, COX-2 selective inhibitors such as celecoxib; all non-selective NSAIDs cross-react.
What are the prerequisites for aspirin desensitisation?
Controlled asthma with stable lung function (FEV1 above roughly 60–70% of predicted), a monitored setting with resuscitation access, cleared nasal disease, and commitment to uninterrupted daily aspirin afterwards.
What benefit does aspirin desensitisation offer?
Reduced nasal polyp regrowth and revision surgery, improved sense of smell, fewer corticosteroid courses, and better asthma control in responsive patients — maintained only while daily dosing continues.