Study On Non-asthmatic Perennial Allergic Rhinitis - Can Atopic Status Predict Development Of Bronchial Hyper-reactivity?

Abstract

RATIONALE: To study the presence of Atopy by skin prick test in non-asthmatic perennial allergic rhinitis patients and its correlation with BHR. METHODS: Thirty three non-asthmatics (no asthma like symptoms and normal spirometry) of perennial allergic rhinitis (PAR) patients were studied. Skin prick test (SPT) with allergens and Histamine bronchial challenge test were done in all the cases at V.P. Chest Institute, University of Delhi, Delhi, India, after the Ethical clearance from the Institute. RESULTS: The patients were of both sexes, aged 12 to 45 years. None of them had any symptom suggestive of asthma or any other respiratory/systemic disease. All had family history of atopy. Out of them, 90% (30/33) were positive by SPT, and 80% (26/33) have demonstrated positive BHR. There was good agreement between positive SPT and BHR (Cohen's kappa = 0.62). It was found that PC20 dose decreases i.e. more hyper-reactivity, as the number of SPT positive allergen increases. The mean PC20 dose was 0.682 ± 0.69 mg/ml in patients who were SPT positive with > 4 allergen, 1.930 ± 1.68 mg/ml in 2-4 and 2.05 ± 1.2 mg/ml in single allergen (P = 0.03 for >4 vs. 2-4 SPT responses, P = 0.04 for > 4 vs 1 SPT response). Three SPT negative patients did show normal level of PC20 Histamine (<8 mg/ml). CONCLUSIONS: SPT positivity among non-asthmatic perennial AR population can predict development of BHR, and can be used as a marker of the march towards development of asthma. These should be screened regularly for development of asthma.