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Nasal eosinophilia in children: its use in the nasal allergen provocation test
R Jean1, A Lellouch-Tubiana, D Brunet-Langot
1Service de Pneumo-Allergologie Infantile, Hôpital des Enfant Malades, Paris, France.
Insights
Nasal eosinophilia during nasal provocation tests can identify allergens in children. These tests are safe, even for children with asthma, aiding in diagnosing allergic rhinitis.
Area of Science:
- Pediatric Allergy and Immunology
- Cytology
- Clinical Medicine
Background:
- Allergic rhinitis is common in children.
- Identifying specific allergens is crucial for effective management.
- Nasal eosinophilia is a potential biomarker for allergic inflammation.
Purpose of the Study:
- To evaluate the utility of nasal eosinophilia in nasal provocation tests (NPTs) for allergen identification in children.
- To assess the safety of NPTs in pediatric patients, including those with asthma.
Main Methods:
- A cohort of 50 children (aged 4-18) with allergic rhinitis or nonatopic chronic rhinitis underwent NPTs.
- Nasal secretions were collected and stained to quantify eosinophils before and after allergen challenge.
- NPTs were considered positive with a >10% increase in nasal eosinophils post-challenge.
Main Results:
- Nasal provocation tests successfully identified offending allergens by measuring increased nasal eosinophilia.
- The tests were found to be safe, with no adverse effects on bronchial resistance, even in children with co-existing asthma.
Conclusions:
- Nasal eosinophilia during NPTs is a valuable tool for diagnosing allergen-specific allergic rhinitis in children.
- Nasal provocation testing is a safe and effective diagnostic method in pediatric allergy, including in asthmatic children.
Abstract:
This pediatric cytological and clinical study aimed at assessing the value of nasal eosinophilia during nasal provocation tests for identifying an offending allergen. The population studied comprised 50 children aged from 4 to 18 yr; 39 of these had well-characterized allergic rhinitis, which in 21 cases was combined with asthma, and the remaining 11 had nonatopic chronic rhinitis. Nasal secretions, collected by nose blowing, were stained with May-Grünwald-Giemsa or Wright stain. The percentage of nasal eosinophils was obtained by examining the cells in the whole slides. Counts were carried out on secretions collected before challenge, after insufflation of saline solution (for verification), and 40 min after insufflation into each nostril of an allergen (housedust mite extract). The nasal provocation test was considered positive when insufflation of the allergen increased nasal eosinophilia by more than 10%, provided that the prechallenge proportion of eosinophils was less than 50%. No increase in specific bronchial resistance was noted. These results indicate that nasal provocation tests are safe, even in asthmatic children.