Clinical Characteristics, Urinary Leukotriene E4 Levels, and Aspirin Desensitization Results in Patients With NSAID-Induced Blended Reactions

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Evaluation of different protocols for classification of pediatric hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: Children with underlying allergic disease should be a separate subgroup

Background: Different recommendations for the classification of nonsteroidal anti-inflammatory drug hypersensitivity reactions (NSHSR) in children have been reported but a shortage still exists. Objective: The aim of the present study was to evaluate the inclusivity of two European Academy of Allergy and Clinical Immunology (EAACI) position paper classifications and to characterize the factors that underlie classification discordance in children. Methods: Patients with a history of NSHSR were evaluated with a standardized diagnostic protocol according to EAACI/ European Network for Drug Allergy (ENDA) recommendations. Children were classified and compared according to the EAACI 2013 and the pediatric EAACI/ENDA 2018 classifications. Subjects who were unclassified and those who were classified were compared. Results: Of 232 patients (median [interquartile range] age 6 years (4-11 years) with a history of NSHSR, 52 (22.4%) were confirmed with diagnostic tests. Thirty-six (69.2%) were classified as having cross-intolerance, whereas 16 patients (30.8%) were classified as selective responders. Eleven of the confirmed cases (21.2%) could not be categorized according to the 2013 EAACI classification, whereas this number was six adolescents (11.5%) when the 2018 EAACI/ENDA pediatric classification was used. Patients who were unclassified and who were all cross-intolerant were more likely to have atopic sensitization (p = 0.001) and asthma as an underlying disease (p = 0.03), higher serum eosinophil count (p = 0.022), and total immunoglobulin E levels (p = 0.007) compared with those who fit well into the classification. In multivariate regression analysis, the presence of atopic sensitization (adjusted odds ratio 20.36 [95% confidence interval, 2.14-193.48]; p = 0.009) was found to be the only significant underlying factor for an unclassified and/or blended phenotype. Conclusion: The 2013 EAACI classification resulted in a high rate of subjects who were unclassified. Despite better clinical utility, the recent pediatric EAACI/ENDA classification system still has shortcomings in terms of inclusivity for adolescents. Mostly, children with underlying allergic diseases could not be classified by the current guidelines. We propose to classify them as a separate pediatric cross-intolerance subgroup because the underlying mechanism may involve more than cyclooxygenase 1 inhibition.

Evaluation and Updated Classification of Acute Hypersensitivity Reactions to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): NSAID-Exacerbated or -Induced Food Allergy

BACKGROUND

There are hypersensitivity reactions (HRs) to foods in which nonsteroidal anti-inflammatory drugs (NSAIDs) act as aggravating factors (NSAID-exacerbated food allergy [NEFA]) or cofactors (NSAID-induced food allergy [NIFA]), often misdiagnosed as HRs to NSAIDs. Urticarial/angioedematous and/or anaphylactic reactions to two or more chemically unrelated NSAIDs do not meet current classification criteria. However, they may be considered part of a cross-reactive type of acute HR, which is NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis.

OBJECTIVE

To evaluate patients reporting acute HRs to NSAIDs and classify them according to updated criteria.

METHODS

We prospectively studied 414 patients with suspected HRs to NSAIDs. For all whom met these criteria, NEFA/NIFA was diagnosed: (1) mild reactions to (NEFA) or tolerance of (NIFA) the suspected foods without taking NSAIDs; (2) cutaneous and/or anaphylactic reactions to the combination foods plus NSAIDs; (3) positive allergy tests to the suspected foods; and (4) negative drug challenges (DCs) with the NSAIDs involved.

RESULTS

A total of 252 patients were given the diagnosis of NSAID hypersensitivity (60.9%), 108 of whom had NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis. We excluded NSAID hypersensitivity in 162 patients (39.1%) who tolerated DCs with the suspected NSAIDs, nine of whom received a diagnosis of NEFA, and 66 of NIFA. Pru p 3 was implicated in 67 of those 75 patients who received a diagnosis of NEFA or NIFA.

CONCLUSIONS

NEFA and NIFA account for about 18% of patients reporting HRs to NSAIDs, in which Pru p 3 is the main responsible food allergen. Therefore, patients with cutaneous and/or anaphylactic reactions to NSAIDs should be carefully questioned about all foods ingested within 4 hours before or after NSAID exposure, and targeted food allergy tests should be considered in the diagnostic workup of these patients. If testing is positive, DCs with the suspected NSAIDs should also be considered.

Emerging Biomarkers Beyond Leukotrienes for the Management of Nonsteroidal Anti-inflammatory Drug (NSAID)-Exacerbated Respiratory Disease

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is a unique condition characterized by aspirin/NSAID hypersensitivity, adult-onset asthma, and/or chronic rhinosinusitis with nasal polyps. Arachidonic acid metabolism dysregulation and intense eosinophilic/type 2 inflammation are central mechanisms in NERD. Studies have been conducted on various biomarkers, and urinary leukotriene E4 is considered the most available biomarker of NERD. However, the pathophysiology of NERD is heterogeneous and complex. Epithelial cells and platelets can interact with immune cells in NERD, and novel biomarkers related to these interactions have recently been investigated. We summarize emerging novel biomarkers of NERD and discuss their roles in the management of NERD.