PURPOSE OF THE STUDY.
The authors investigated whether history of parental atopic diseases are associated with a higher risk of reaction to common allergenic foods in children.
In this Dutch study, 396 children (251 male, 145 female) with suspected food allergy were recruited from a pediatric allergy outpatient clinic. Median age was 5.4 years (range, 6 months to 17.8 years).
The parents and children were asked if they each had a previous diagnosis of asthma, allergic rhinitis, atopic dermatitis, or (in the parents) food allergy. Children were identified as having food sensitivity through an elevated ImmunoCap-specific IgE (>0.35 kU/L) to cow’s milk, hen’s egg, peanut, or hazelnut. The children also underwent double-blind, placebo-controlled food challenges (DBPCFC) to the allergenic food, with a period of at least 2 weeks between food and placebo challenges. Logistic regression analysis was used to compare risk of a reaction to each food tested between children whose parents were not atopic and children with 1 or 2 parents with atopic diseases.
More than 90% of the children had been previously diagnosed with atopic disease, most commonly eczema. A total of 553 DBPCFCs were performed with 274 children tested for 1 food, 92 for 2 foods, 25 for 3 foods, and 5 for all 4 foods. Foods tested included cow’s milk (n = 185), egg (n = 110), peanut (n = 198), and hazelnut (n = 60). Parental eczema was significantly associated with reaction to milk oral challenges (odds ratio 3.1, 95% confidence interval 1.5–6.3, P < .01) even after corrected for age, sex, serum IgE test results, and atopic comorbidity. Among children challenged with egg, peanut, or hazelnut, there was no significant association with parental eczema. Other parental atopic conditions (allergic rhinitis, asthma) were not associated with clinical reactivity to any of the foods. There was also no statistically significant effect for increasing number of parental atopic conditions on the risk of reaction to any of the foods.
There may be more shared genetic factors between clinical reactivity to milk and parental eczema than there are with other allergenic foods.
Pediatricians and allergists are often asked if an infant has an increased risk of developing a food allergy based on family history, and this Dutch study suggests parental eczema may be a risk factor for cow’s milk allergy. However, there are still many questions regarding familial and environmental influences on atopic development in young children. What is the definitive answer regarding food avoidance and pregnancy, when is the “safest” time to introduce the more allergenic foods into a child’s diet, and what are the gene(s) that are more involved in atopic diseases? This promises to be a challenging field of study in which large, multicentered trials will help us begin to answer these questions.
- Copyright © 2012 by the American Academy of Pediatrics