Australian researchers believe it may be possible to predict which children will
eventually outgrow peanut allergies.
The study, presented as a briefing at the recent American Academy of Allergy, Asthma and Immunology annual meeting in San Diego, followed young children with identified peanut allergies for up to nine years.
Dr Katie Allen and colleagues from the
Royal Children's Hospital in Melbourne reported that patterns in immunoglobulin E levels and the diameter of wheals raised during skin prick testing could predict whether peanut allergies would go into remission.
"One of the first questions that parents ask when their child is diagnosed with peanut allergy is whether the child will grow out of it," Dr Allen said.
"It's obviously of concern to them and a lot know that a small proportion will not have lifelong peanut allergy."
To see whether they could identify early clinical predictors of allergy, the investigators identified children younger than two years old who had been referred on the basis of an unequivocal history of allergic reactions and/or skin prick tests.
They performed skin prick tests yearly until either levels were below those that were more than 95 per cent likely to predict a clinical reaction to peanuts or when a child accidentally ingested peanuts and was able to tolerate them.
They found that 21 per cent of the children had remission of presumed peanut allergy by age five, and that prognosis of peanut allergy could be predicted by either a constant rise, or constant fall in the level of immunoglobulin E (IgE) sensitisation to peanut by age three.
The investigators determined that a child was two to three times less likely to develop tolerance to peanuts if they had a wheal diameter on skin prick tests that was 6mm or larger before age two.
"A 3mm or greater rise of skin prick test wheal size between one and four years of age was strongly predictive of persistent peanut allergy whereas as falling levels was a good prognostic sign," Dr Allen said.
The researchers found that neither the severity of the initial clinical reaction, gender, age at diagnosis, total IgE levels, presence of asthma or other food allergies or early inhalation allergen sensitisation were associated with the prognosis for peanut allergy.
As well, although allergies to tree nuts and to sesame were more common in the group of children who remained allergic to peanuts, neither of these former sensitivities were predictive of the rate of remission.
The authors concluded that the "size and annual rate of change of skin prick testing over time can be helpful in prediction of peanut allergy remission".
NB. This is a preliminary study which has not yet been reviewed and published.
Outgrowing Peanut Allergy
