Abstract
Introduction: The controlled allergen exposure to patients in EECs allows for the direct comparison of perennial and seasonal allergies and asthma. Comorbidity between allergic rhinitis and asthma is high for perennial allergens like house dust mite and cat. Our previous EEC studies support this finding.
Objective: To examine asthma symptoms scores reported in patients with or without mild to moderate asthma exposed to birch allergen in an EEC and to record the incidence and severity of asthma symptoms observed in the EEC.
Methods: 255 birch allergic subjects, with or without mild to moderate asthma, were screened for birch allergy based on medical history a positive skin prick test (STP) to birch allergen (wheal size>3mm) and an IgE class 2 or higher and were exposed to birch allergen in an EEC for 6 hours. During this time subjects reported asthma symptom scores (cough, wheeze, chest tightness, dyspnea) on a 4-point scale (0 none; 1 mild; 2 moderate; 3 severe) pre chamber entry, and every 30 minutes post entry for the duration of the visit.
Results: Total asthma symptom scores (TASS) (the sum of the 4 individual asthma symptom scores) were analyzed for the 255 subjects exposed to birch allergen in the EEC. Of these subjects, approximately 15% had a history of mild to moderate asthma. During the EEC challenge, only 19% of subjects scored ≥ 6/12 for TASS on at least one diary card, 12% of subjects scored ≥8/12 and only 3.5% of subjects scored ≥10/12.
Conclusion: This study suggests fewer birch allergic patients experience asthma symptoms and that seasonal allergies such as birch are associated with less asthma than observed in perennially allergic patients.
- Copyright ©ERS 2015
