[Food allergy in children. II. Prognostic factors and long-term development]

The evolution of 109 allergic children with 129 IgE-mediated food sensitizations has been evaluated. The follow-up period was from nine months to 14 years. The period up to clinical tolerance was analyzed, together with the influence of two possible prognostic factors: specific IgE antibody levels at the beginning of symptomatology and the sensitizing food. Moreover, when clinical tolerance was achieved, the presence of specific IgE antibodies was again assessed. Probability estimations indicated that 30% of food-allergic children become clinically tolerant before 3 years of evolution, 40% before 6 years, 50% before 9 years and 53% before 12 years. Onset of clinical tolerance varies in dependence with the offending food: clinical tolerance to cow's milk seems to be far earlier and easier to reach than those to egg and fish (p less than 0.001, at 9 years' evolution); allergy to egg disappears also earlier and easier than fish allergy (p less than 0.01). Levels of specific IgE antibodies at the onset of the disease show significant difference (p less than 0.01) between the patients which will become tolerant and those with persistence of clinical sensitivity, being higher in the last group. However, a high number of patients who become clinically tolerant (67.5%) remained positive at skin prick testing or had elevated specific IgE serum antibodies against the offending food.