PURPOSE OF THE STUDY.
To characterize the risk of challenge-proven food allergy among infants with eczema in the general population.
Infants were recruited from the general population at their immunization sessions in Melbourne, Australia. Recruitment took place between September 2007 and August 2011, and all infants were 11 to 15 months of age; 7134 infants were eligible for study, 5276 (74%) agreed to participate, and 4453 met criteria to be used in final study analysis.
One-year-old infants were examined for eczema on the face, back, and elbows by a trained nurse and underwent skin prick testing to peanut, egg, and sesame. Those with any detectable wheal to 1 of the test foods underwent an open oral food challenge to that food. Parents completed a questionnaire regarding age of onset of eczema, medication use, and environmental and demographic factors. The risk of food allergy stratified by eczema severity, age of onset, and medication usage was estimated using multivariate logistic regression with population sampling weights.
One in 5 infants with eczema had confirmed allergy to peanut, egg white or sesame by 12 months, compared with 1 in 25 infants without eczema (odds ratio = 6.2, 95% confidence interval [CI]: 4.9–7.9, P < .001). Infants with eczema were also 11 times more likely to develop peanut allergy (95% CI: 6.6–18.6) and 5.8 times more likely to develop egg allergy (95% CI: 4.6–7.4) than infants without eczema. The risk of peanut or sesame seed allergy was low in the absence of eczema (0.7% 95% CI 0.4–1.1). Fifty percent of infants (95% CI: 42.8–58.9) with early -onset eczema (<3 months) who required doctor-prescribed topical corticosteroid treatment developed challenge-proven food allergy by 12 months of age.
Infants with eczema were 6 times more likely to have egg allergy and 11 times more likely to have peanut allergy by 12 months than infants without eczema. The data suggested that a heightened awareness of food allergy risk is warranted among health care practitioners treating infants with eczema.
This study confirms a strong association between eczema in infancy and the development of food allergy. Its strengths lie in the fact that it assesses a large general infant population, not a selection-biased group from a tertiary allergy or dermatology referral practice. It also uses food challenges to confirm the presence of food allergy. Because infants with eczema often have clinically irrelevant IgE antibodies to foods, a positive food challenge represents a more accurate determination of true food allergy. Currently National Institute of Allergy and Infectious Diseases–sponsored guidelines do not recommend screening infants with eczema for food allergies unless they have severe refractory eczema or a history of a reaction to a food. Fifty percent of infants with early-onset eczema (<3 months) and moderate to severe eczema (requiring prescription topical corticosteroids) may develop “real” food allergy by 12 months. Clinicians should be proactive to assess food allergy in this group and attempt prevention strategies by inducing primary oral tolerance with early introduction of foods or minimizing allergen exposure through weakened skin barriers. Although more research is needed to identify optimal prevention strategies, the development of food allergy appears to occur earlier than previously suspected.
- Copyright © 2015 by the American Academy of Pediatrics