World Allergy Organization Updates NSAID Hypersensitivity Classification
WAO Updates NSAID Hypersensitivity Reaction Classification & Diagnosis
The World Allergy Institution (WAO) has recently updated its classification and diagnostic framework for non-steroidal anti-inflammatory drugs (NSAIDs) hypersensitivity reactions. These updates include:
Recognition of blended reactions: Reactions involving two organ systems (e.g., skin and respiratory, skin and gastrointestinal). Extension of pediatric classifications to adults: Specifically, adopting the acronym NIUAA (NSAID-induced urticaria/angioedema/anaphylaxis) for mild anaphylactic reactions.
Introduction of mixed N-ERD and mixed NECD subgroups.
Inclusion of NSAID-exacerbated and NSAID-induced food allergy.
According to lead author antonino Romano and colleagues, the updated WAO Statement clarifies both the classification and diagnosis of these reactions. Patients reporting reactions to two chemically unrelated NSAIDs, with symptoms like urticaria/angioedema and/or involvement of two organ systems, are now classified as having NSAID-induced urticaria/angioedema/anaphylaxis.
Current Guidelines & Acute Reaction Types:
Existing US and European guidelines categorize hypersensitivity reactions to NSAIDs as either acute (≤ 6 hours) or delayed (> 6 hours or > 24 hours). Acute reactions are further divided into:
Aspirin/NSAID-exacerbated respiratory disease
NSAID-exacerbated cutaneous disease
NSAID-induced urticaria/angioedema
Single NSAID-induced urticaria/angioedema/anaphylaxis
N-ERD (Aspirin-Exacerbated Respiratory Disease):
The WAO statement also details N-ERD, a condition characterized by a triad of:
Asthma
chronic rhinosinusitis with nasal polyps (CRSwNP)
Respiratory reactions to cyclooxygenase (COX)-1 inhibitors
Key points about N-ERD:
Onset: Typically develops in patients in their 30s and 40s, but can range from puberty to the 80s.
Prevalence: 0.1% to 0.6% in population-based studies.
Pathophysiology: linked to disturbances in the COX and 5-lipoxygenase pathways of arachidonic acid metabolism.
Symptoms: Include nasal congestion, rhinorrhea, sneezing, nasal pruritus, ocular chemosis, and bronchospasm within 30 minutes to 3 hours of COX-1 inhibitor exposure.
Comorbidities: Frequently enough associated with CRSwNP and olfactory disturbances.
* Extra-respiratory Symptoms: Approximately 20% of patients experience symptoms like skin rashes, urticaria, angioedema, chest pain, abdominal pain, nausea, vomiting, and diarrhea.
Source: https://www.hcplive.com/clinical/allergy (Reference 1)
References:
- WAO Statement on NSAID hypersensitivity reactions.
- US guidelines on hypersensitivity reactions to NSAIDs.
- European guidelines on hypersensitivity reactions to NSAIDs.