The aim of this study was to investigate whether the duration of sensitization to food allergens during early childhood was predictive of the later development of immunoglobulin E (IgE) mediated hypersensitivity to inhalant allergens, allergic rhinitis, and asthma.
The prospective birth study cohort was derived from five German cities and consisted of 499 infants at “high-risk” for atopic disease and 815 infants without risk factors for atopic disease. The children were followed through 5 years of age and of these, serum samples were available on 508 children. Specific sensitizations to food (milk, egg, soy, and wheat) and inhalant (dust mite, cat dander, grass pollen, and birch pollen) allergens were determined at 1, 2, and 5 years of age with the CAP-RAST FEIA (Pharmacia & Upjohn; Uppsala, Sweden). History and physical examination were used to establish the diagnosis of subsequent allergic airway disease.
Children with a long-lasting sensitization to food allergens (persistently sensitized for more than 1 year) had significantly greater total IgE and specific IgE concentrations than children who were food-sensitized only transiently in the first 2 years of life. Children with persistent sensitivity to food had a 3.4-fold greater risk of developing allergic rhinitis and a 5.5-fold greater risk of developing asthma than infants who were only transiently sensitized to foods.
Persistent food sensitization in young children with a positive atopic family history is a strong predictor for the development of allergic rhinitis and asthma by 5 years of age, up to 50%, and 67%, respectively. Persistently detectable IgE antibodies to a food over more than 1 year in early childhood is a strong prognostic indicator of subsequent allergic airway disease. Persistently food-sensitized children, especially in atopic families, have to be regarded at high-risk for respiratory allergy and should be considered for preventive measures.
With the increasing prevalence of allergic disease in westernized societies, investigators are trying to identify simple screening measures to distinguish children at “risk.” This study suggests that identifying children with IgE antibodies to any of a few common foods (presumably by prick skin tests or radioallergosorbent tests) will provide a simple, inexpensive way to identify children at risk for later allergic respiratory disease, who then might benefit from prophylactic measures.