Natural course and factors associated with allergic diseases in the first 2 years: Data from a Developing Asian Countries

Allergic diseases have been increasing in the last few decades. Interplay between genetic and environmental factors underlined these complex diseases. Data concerning epidemiology, natural history and factors associated with allergic diseases in developing Asian countries are limited. A population-based birth cohort study was conducted since July 2015 to August 2018 in Bangkok, Thailand. Diagnosis of allergic diseases was confirmed by allergists. Oral food challenges were performed for the diagnosis of food allergy. Three hundred and sixty nine mother-children pairs were enrolled in the study. The incidence of allergic diseases was 21.6%, including 13.3% of atopic dermatitis (AD), 8.2% of food allergy and 3.5% with both AD and food allergy. Maternal history of allergic diseases and infant exposure to antibiotics before 6 months increased risk of food allergy with the hazard ratio (HR) of 3.14(1.25-7.88),p=0.015 and 3.97(1.52-10.34),p=0.005 respectively. No factor was found to be associated with AD. AD was outgrown in 55.8% and 62.1% at the age of 12 and 24 months, regardless of severity, onset of disease and food allergy status. Outgrowing food allergy was found in 42.9% and 71.4% at 12 and 24 months respectively, regardless of types of food allergic reaction, food allergens, onset of disease and atopic dermatitis status. Twenty percent of children in a developing Asian country develop allergic diseases in early life. However, nearly two thirds of children had outgrown by the age of two. Maternal atopy and early life exposure to antibiotic associated with food allergy. Appropriate antibiotic use should be considered.