April 1, 2011 (San Francisco, California) — The first longitudinal multicenter investigation of milk allergy in children has found that several factors predict resolution of this allergy without intervention. Predictors include smaller wheals on skin prick testing and lower milk immunoglobulin E (IgE) values, according to researchers here at the American Academy of Allergy, Asthma and Immunology (AAAAI) 2011 Annual Meeting.
In the study of 244 children with milk allergies, 89 had outgrown their food allergies after 30 months of follow-up, indicating that the children had a 40% probability of resolution of milk allergies, according to study author Robert Wood, MD, professor of pediatrics and chief of pediatric allergy and immunology at Johns Hopkins Children's Center, Baltimore, Maryland. The median age at resolution of milk allergy was 2 years.
The factors that predicted resolution were smaller wheals on skin prick testing at baseline (median, 5 mm for children whose allergies resolved vs 9.25 mm for those whose allergies did not) and milk-specific IgE levels less than 2, Dr. Wood said.
Seventy-five percent of children with milk-specific IgE levels of less than 2 outgrew their allergies by 30 months, the study showed. "It's very helpful for both pediatricians and patients to be able to predict the possibility of resolution of allergies," Dr. Wood said. Such knowledge can help clinicians determine how often a child should be followed and can determine whether or not interventions such as food desensitization should be attempted, he noted.
Other research from the same cohort presented here at the AAAAI annual meeting indicated that severity of eczema can predict whether a child will outgrow milk or egg allergies. Eczema severity was scored at baseline and at 2 years and was categorized as none-mild or moderate-severe. Milk and egg allergies were assessed based on clinical history, food-specific IgE blood tests, and skin prick tests. Resolution of the allergies was determined by ingestion of the trigger food without symptoms.
Although clinicians often presume that when eczema improves, food allergy will also resolve, the study's findings did not support this theory, Dr. Wood said. Improvement in eczema symptoms in the children was not significantly associated with resolution of either milk or egg allergies, he added.
In the study, 46% of 59 children with no or mild eczema experienced resolution of milk allergy vs 25% of 165 children with moderate or severe eczema (P = .0004) after 2 years. In children with egg allergy, 39% of 33 children with no or mild eczema at enrollment resolved their egg allergy after 2 years vs 21% of 89 children with moderate to severe eczema at baseline.
These 2 studies provide clinicians with important information about which patients are more likely to outgrow milk and egg allergies, and also suggest that genetics may be more important than environmental factors in resolution of these allergies, commented allergist and immunologist Jeffrey Factor, MD, associate clinical professor of pediatrics at the University of Connecticut School of Medicine, Farmington, and medical director of the New England Food Allergy Treatment Center, West Hartford, Connecticut.
"The historical belief was that the vast majority of children with milk allergy will outgrow it by age 5, and many — about 85% — outgrow it after the first year of life. This research tells us that it takes longer for children to outgrow milk allergies than we thought," Dr. Factor said. "Although many children do outgrow milk allergy, it's not as significant a number as we once thought, and many do not outgrow it until the second decade of life," he said.
Dr. Factor also noted that the relationship of eczema symptoms to food allergy persistence indicates that early presentation of symptoms is an important predictor of whether or not such allergies resolve. "It's interesting that the children who experienced improvement in their eczema did not outgrow their milk or egg allergy to a greater extent than those whose moderate to severe symptoms stayed the same," he said. "This suggests that whether or not you outgrow food allergies may be more likely to be determined by genetics than environmental changes or factors," he said.
Dr. Wood and Dr. Factor have disclosed no relevant financial relationships.
American Academy of Allergy, Asthma and Immunology (AAAAI) 2011 Annual Meeting: Abstract 126, Abstract 268. Presented March 19, 2011.
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