Rate of severe reactions higher than thought in young children with food allergies

"This study reinforces the importance of doctors, parents and other caregivers working together to be even more vigilant in managing food allergy in children," said Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The study results appear online in the June 25 issue of Pediatrics and are the latest findings from the Consortium of Food Allergy Research (CoFAR), a network established by NIAID to conduct clinical trials, observational studies and basic research to better understand and treat food allergy.

The research is part of an ongoing CoFAR observational study that enrolled 512 infants aged 3 to 15 months who at study entry were allergic to milk or egg, or who were likely to be allergic, based on a positive skin test and the presence of moderate-to-severe eczema, a chronic skin condition. The investigators are carefully following these children to see whether their allergies resolve or if new allergies, particularly peanut allergy, develop. The study is ongoing at research hospitals in Baltimore; Denver; Durham, N.C.; Little Rock, Ark.; and New York City.

CoFAR investigators advised parents and caregivers to avoid giving their children foods that could cause an allergic reaction. Study participants also received an emergency action plan, describing the symptoms of a severe allergic reaction to food and what to do if a child has one, along with a prescription and instructions on how to give epinephrine if a severe reaction occurred.

Data compiled from patient questionnaires and clinic visits over three years showed that 72 percent of the children had a food-allergic reaction, and that 53 percent of the children had more than one reaction, with the majority of reactions being to milk, egg or peanut. This translated into a rate of nearly 1 food-allergic reaction per child per year. Approximately 11 percent of the reactions were classified as severe and included symptoms such as swelling in the throat, difficulty breathing, a sudden drop in blood pressure, dizziness or fainting. Almost all of the severe reactions were caused by ingestion of the allergen rather than inhalation or skin contact.

In only 30 percent of the severe reactions did caregivers administer epinephrine, a drug that alleviates the symptoms of severe reactions by increasing heart rate, constricting blood vessels and opening the airways. Investigators found that caregivers did not give children epinephrine for a number of reasons: the drug was not available, they were too afraid to administer it, they did not recognize the symptoms as those of an allergic reaction, or they did not recognize the reaction as severe.

"This study documenting the natural history of allergic reactions to three of the major food allergens in pre-school children provides important new information for parents, caregivers and health care workers because of the large number of children involved and the rigorous follow-up," said Daniel Rotrosen, M.D., director of the NIAID Division of Allergy, Immunology and Transplantation, which oversees CoFAR. "The findings not only reveal that food-allergic reactions occur at a much higher rate in young children than we thought, they also suggest that more vigilance and increased use of epinephrine is needed."

Almost 90 percent of allergic reactions to egg, milk or peanut occurred after a child accidentally ate the food. The reasons for the accidental exposures included caregivers misreading food labels, not checking a food for an allergen, and unintentionally allowing a food allergen to come into contact with other foods (cross-contamination).

The study also found that approximately 11 percent of allergic reactions to egg, milk or peanut occurred after a caregiver -- most often a parent -- provided a child the allergenic food intentionally.

"Intentional exposures to allergenic food are typically reported in teenagers, who tend to take more risks or who might be embarrassed about their food allergy," says David Fleischer, M.D., the lead study author. "What is troubling is that in this study we found that a significant number of young children received allergenic foods from parents who were aware of the allergy."

CoFAR investigators are exploring possible reasons for these intentional exposures, but they speculate that it could reflect parents' at-home tests to determine if children have outgrown the food allergy. Because giving children allergenic foods could possibly result in life-threatening reactions, such testing should only be conducted under the direct supervision of a health care professional trained in performing food challenges. The study findings reinforce the importance of caregivers working closely with their doctors to understand how to effectively manage a child's food allergy.