Type | Eliciting NSAID | Signs and symptoms | Timing of onset of signs/symptoms | Patient comorbidities |
Pseudoallergic NSAID reactions: - Elicited by multiple NSAIDs (including aspirin) in a susceptible patient
- Related to the pharmacologic ability of NSAIDs to inhibit COX-1 enzyme
|
Type 1 | Multiple (including aspirin) | Common: - Severe rhinitis, nasal obstruction
- Bronchospasm
- Conjunctival injection
- Facial flushing
Uncommon: - Throat tightness/laryngospasm
- Nausea/vomiting
- Diarrhea
- Hypotension
| Delayed: 30 minutes to three hours after ingestion or administration | - Asthma (present in most but not all patients)
- Chronic rhinosinusitis with nasal polyposis (patients usually have extensive sinusitis on CT and often report anosmia)
- AERD*
|
Type 2 | Multiple (including aspirin) | Urticaria and/or angioedema | 30 to 90 minutes | Chronic urticaria (patients may report being able to tolerate NSAIDs when urticaria is in remission) |
Type 3 | Multiple (including aspirin) | Urticaria and/or angioedema | 30 to 90 minutes | None |
Type 4 | Multiple (including aspirin) | Symptoms affecting both the respiratory tract and skin. Includes patients with AERD who develop cutaneous symptoms in the context of respiratory reactions. | Variable depending upon the type of reaction: 30 to 90 minutes | - Some patients have AERD and experience systemic reactions with cutaneous symptoms
- Other patients have no underlying conditions
|
Allergic NSAID reactions: - Elicited by a single NSAID (or rarely by more than one agent with very similar structure) in a susceptible patient
- Not reported with aspirin
- Presumed to be IgE-mediated
|
Type 5 | A single NSAID (not aspirin) | Cutaneous: Urticaria, pruritus, angioedema | Variable: Minutes to a few hours after ingestion/administration | None |
Type 6 | A single NSAID (not aspirin) | Anaphylaxis (probably a more severe form of type 5) | Variable: Minutes to a few hours after ingestion/administration | None |