Prevalence of Allergic Sensitization in Childhood Asthma

Introduction The allergic sensitization in childhood asthma is common and the prevalence varies in different geographical locations. The data on allergen sensitization to guide clinicians on allergy avoidance is limited. Method This prospective observational study was conducted between October 2019 and April 2020 on children aged two to 14 years attending an outpatient clinic. Those with recurrent wheezing or physician-diagnosed asthma were interviewed; eosinophil count, total serum immunoglobulin E (IgE) was measured; and skin prick test (SPT) was done using standardized reagents. Wheal size of ≥3mm was considered positive. Results A total of 80 children were enrolled. The mean age was 71.15 ± 33.52 months (M:F ratio =1.96:1). Allergic rhinitis, conjunctivitis, and dermatosis were seen in 76 (95.0%), 33 (41.3%), and 22 (27.5%) cases, respectively. The mean absolute eosinophil count was 576 ± 427per cmm. The mean total IgE was 800.9 ± 883.2IU/ml. Seasonal and diurnal variations were found in 34 (42.5%) and 79 (98.8%) cases. Out of 1753 skin pricks using 27 reagents, 355 (20.25%) were positive. Increasing age was significantly associated with increasing SPT positivity (P = 0.0001). The most common sensitive aeroallergens were Kentucky bluegrass (25%), Dermatophagoides pteronyssinus (22.5%), Dermatophagoides farinae (21.3%), Timothy grass, and Alternaria alternans (20% each). The most common sensitive food allergens were spinach (25%), banana (22.5%), carp (20%), shrimp and hen’s egg (18.8% each), and cow’s milk (17.5%). Conclusion Increasing age was associated with increasing SPT positivity in childhood asthma. The most common sensitive aeroallergens were Kentucky bluegrass and Dermatophagoides pteronyssinus; spinach and banana were the most common food allergen.