113 Association between degree of sensitivity to indoor allergens and asthma severity

• Published in: BMJ paediatrics open Vol. 5; no. Suppl 1; pp. A33 - A34
• Main Author: Tin, Wai Mar
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group LTD 01.04.2021; BMJ Publishing Group
• Subjects: Allergens; Allergies; Asthma; Indoor air quality; Pediatrics
• ISSN: 2399-9772
• DOI: 10.1136/bmjpo-2021-RCPCH.64

BackgroundAeroallergens, especially indoor aeroallergens have a major role in the pathogenesis and severity of asthma. In Myanmar, data about allergen sensitivity and asthma is still lacking. Understanding the prevalence of the most common aeroallergens in local area can help in the diagnosis and management of asthma.ObjectivesTo determine the prevalence of sensitivity of indoor allergens in children with asthmaTo analyze the association between degree of sensitivity to indoor allergens and asthma severity.MethodsThis hospital based cross sectional analytical study was conducted in 120 children (aged 6–12 years) with asthma who attended asthma clinic in Yangon Children Hospital. Severity of asthma was assessed by taking history, physical examination and lung function test. It was classified into mild asthma and moderate to severe asthma groups according to the working definition. Skin prick test with eight indoor aeroallergens extracts was performed in 120 children. The degree of the allergic sensitization was assessed by the number of positive skin prick tests and by skin wheal sizes. Associations between degree of atopic sensitization and severity of asthma, were analyzed by using logistic regressionResultsThe majority of subjects (67.5%) had moderate- severe asthma and 32.5% had mild asthma. 92.5% of study population had skin prick test positive to at least one indoor allergen. Mono sensitization to aeroallergen was observed in only 11.7% of patients and the rest were sensitized to more than one allergen among sensitized children. The most prevalent allergen was HDM (Dermatophagoides pteronyssinus and Dermatophagoides farinae) with 64.2% and 68.3% respectively. Prevalence of sensitization to other indoor allergens was as follow: Aspergillus fumigatus (40.8%), Alternaria alternata (34.2%), Cat (51.7%), Dog (50.8%) and cockroaches, Blatella germanica (48.3 8%) and Periplaneta Americana (53.3%). Overall, multiple sensitization (sensitization to >4 allergens) was significantly associated with increasing level of asthma severity (p<0.001). However, that association disappeared after adjustment for potential confounders like age, sex, exposure to smoking, pet and having family history of asthma or allergic rhinitis. It remained statistically significant only for the patients sensitized to HDM as the relationship was not modified by con founders. Moreover, mean SPT wheal size was not significantly associated with severity of asthma for all allergens tested.ConclusionsHDM was the most common sensitizing aeroallergen. Although children with moderate to severe asthma had significantly higher proportion of SPT positive, this study could not establish any relationship between degree of wheal size and severity of asthma. Therefore, the association between degree of sensitivity to indoor allergen and childhood asthma severity is still uncertain.