Natural course of sensitization to food and inhalant allergens during the first 6 years of life

Background: Specific IgE antibody responses to alimentary and environmental allergens are one of the hallmarks of atopic diseases. The knowledge of th e time course of allergic sensitization during early life may facilitate me asures for preventive interventions. Objective: In a prospective birth cohort study (the Multicenter Allergy Stu dy [MAS]) we investigated annual incidence and prevalence Fates of sensitiz ation to food and inhalant allergens during the first 6 years of life. Methods: For 216 children of a prospective birth cohort (MAS), a complete f ollow-up of specific IgE measurements to 9 food and inhalant allergens was available at 1, 2, 3, 5, and 6 years of age. On the basis of these measurem ents, sensitization rates were estimated for the reference population of 40 82 children by weighted analysis. Results: Annual incidence rates of sensitization to food allergens decrease d from 10% at I year of age to 3% at the 6 years of age. Incidences of sens itization to inhalant allergen, however, increased with age (from 1.5% at 1 year to 8% at 6 years). Point prevalences of allergic sensitization to at least 1 of the 9 tested allergens increased from 11% at 1 year up to 30% at 6 years. This increase was due to markedly increasing sensitization rates to inhalant allergens (1.5% to at least 1 inhalant allergen at 1 year and 2 6% at 6 years of age), whereas sensitization rates to food allergens remain ed stable during the first 6 years of life (10%). Conclusion: The earliest serologic marker for atopic immunoreactivity in in fancy is the presence of IgE antibodies to egg, followed by milk. The devel opment of sensitization to inhalant allergens occurs mostly after infancy. Beyond the third birthday annual incidence and prevalence increase markedly with age. Rates for outdoor allergens are twice those for indoor allergens .