[Early introduction of food to prevent food allergy. The LEAP study (Learning Early about Peanut)].

Peanut allergy is an increasing global health problem, which affects 1--3% of children in Western countries. The prevalence may have tripled in the last 15 years, which constitutes approximately 100,000 new cases annually in the USA and Canada.1--3 The most recent evidence, challenging the current guidelines, highlights the benefits of early introduction of peanuts, rather than avoidance, during the infants’ complementary food period. The basis is the study ‘‘Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy (Learning Early About Peanut -LEAP Trial),’’ which demonstrated an absolute decrease of 11--25% in the risk of developing peanut allergy in high-risk children if the food were introduced between 4 and 11 months of age.4 In the LEAP trial, 640 British infants at high risk for allergy, aged 4--11 months, were randomly assigned to consume products that contained peanut at least three times a week (6 g of peanut protein, the equivalent to 24 peanuts or 6 teaspoons of peanut butter a week) or to completely avoid products containing peanuts in the first five years of life. This population included 542 infants with negative skin prick tests at baseline and 98 infants with positive tests, with papule diameter of 1--4 mm to peanut extract. A total of 76 children whose skin tests showed papules larger than 4 mm in diameter, which implied a high probability of responding to peanut challenge, were excluded. In an intent-to-treat analysis, 17.2% of the group that avoided peanut developed a positive peanut challenge test at the age of 5 years compared to 3.2% in the group that consumed the food. This corresponded to a 14% reduction in the absolute risk of reaction, i.e., the necessary number (NNT) of 7.1 treated individuals