Many children outgrow egg allergy

NEW YORK (Reuters Health) - Most children seem to outgrow allergies to eggs, but it may take longer than past research has suggested, according to a new study.

Researchers found that of 881 children who'd been treated for egg allergy at their center, more than two thirds eventually outgrew the allergy. However, it often took longer than past studies have suggested.

Only 4 percent of the children had outgrown their allergy by age 4, the study found, while 37 percent were no longer allergic at age10. By the age of 16, sixty-eight percent had outgrown their egg allergy, the researchers report in the Journal of Allergy and Clinical Immunology.

The good new is that most of these children did overcome their allergy, according to Dr. Jessica H. Savage and colleagues at Johns Hopkins University School of Medicine in Baltimore.

They point out that the largest and most recent study on the question found that half of the children with an egg allergy developed a tolerance for the food before the age of 5.

The researchers speculate that one reason for the discrepancy is that children in the earlier study were not as allergy-prone. In the current study, for example, 81 percent of the children also had the allergic skin eczema in addition to egg allergy.

There was also evidence that children with a particularly strong immune response against egg protein were the least likely to outgrow the allergy. Among children with high levels of immune system proteins called IgE antibodies, the majority were still allergic at age 18.

This suggests that measuring children's IgE concentrations will help predict which ones will probably outgrow their egg allergy eventually - and those will not, according to Savage's team.

Eggs are second only to milk as a cause of children's food allergies, with egg allergies affecting between 1 percent and 2 percent of young children. Avoiding eggs can be difficult, as they are present in many foods and are even used in manufacturing certain vaccines, including the flu shot.

SOURCE: Journal of Allergy and Clinical Immunology, December 2007.