About three out of 10 peanut allergies and nine of 10 egg allergies resolved by age 6 years, although infants with early-onset severe eczema or multiple allergies were less likely to outgrow them, according to a longitudinal study.
These findings may inform the use of disease-modifying treatments such as oral immunotherapy or proactive treatment of eczema in early life, the researchers wrote in the study, which was published in The Journal of Allergy and Clinical Immunology.
“Prioritizing research of these and future interventions for infants less likely to naturally outgrow their allergy would yield the most benefit for health care resources and research funding,” Rachel L. Peters, PhD, associate professor, epidemiologist and team lead within the population allergy research group at Murdoch Children’s Research Institute, Royal Children’s Hospital, in Parkville, Victoria, Australia, said in a press release.
The researchers examined data from the HealthNuts population-based longitudinal study, which tracks the prevalence and natural history of allergic diseases among 5,276 children recruited at age 1 year from council-run immunizations in Melbourne, Australia, from 2007 to 2011. Food allergy testing was performed during the 1-year visit, with follow-up oral food challenges or new testing for patients with new symptoms conducted at 2 (egg only), 4 and 6 years along with parental questionnaires. Although 156 children had a peanut allergy at age 1 year, these allergies resolved in 29% (95% CI, 22-38) of children with definite allergy by age 6 years. Compared with those children whose peanut allergy had resolved by age 6 years, persistent peanut allergy appeared more common among children who had early-onset severe eczema (adjusted OR = 3.23; 95% CI, 1.17-8.88), sensitization to at least one tree nut (aOR = 2.51; 95% CI, 1-6.35) and skin prick test results of 8 mm or larger (OR = 2.35; 95% CI, 1.08-5.12) at 1 year.
Among the 471 children with raw egg allergy at age 1 year, allergies resolved in 89% (95% CI, 85-92) of those with definite allergy by age 6 years. Additionally, compared with children whose egg allergy had resolved, persistent egg allergy was more likely among children with an SPT result of 4 mm or larger (OR = 2.98; 95% CI, 1.35-6.36), peanut or sesame food sensitizations (aOR = 2.8; 95% CI, 1.11-7.03), early-onset severe eczema (aOR = 3.77; 95% CI, 1.35-10.52) and baked egg allergy (aOR = 7.41; 95% CI, 2.16-25.3) when aged 1 year.
During the time children were aged 1 to 6 years, new-onset peanut allergies developed in 0.7% (95% CI, 0.5-1.1), and new-onset raw egg allergies developed in 0.09% (95% CI, 0.03-0.3) of the children. At age 6 years, peanut allergy — including definite, probable and possible outcomes — had an overall weighted prevalence of 3.1% (95% CI, 2.6-3.7), and egg allergy had an overall weighted prevalence of 1.2% (95% CI, 0.9-1.6). Additionally, SPT responses at age 1 year appeared larger among children with persistent food allergy compared with those children whose allergies had resolved, although the researchers cautioned that these test results were poor predictors of predicting peanut allergy prognoses (area under the curve, 0.64; 95% CI, 0.54-0.74) and egg allergy prognoses (area under the curve, 0.68; 95% CI, 0.58-0.78) at age 6 years.
According to the researchers, this was the first study to monitor food allergy status through standardized questionnaires, SPTs and OFCs, and its results highlight how the onset of peanut allergy after age 1 year is a real and potentially increasing problem. Further, the researchers wrote, challenges remain in predicting which patients will outgrow their allergies and when this tolerance will occur. Such information, they continued, would help clinical management, implementation of emerging therapies such as oral immunotherapy, and family counseling. “Prioritizing research of these and future interventions for infants less likely to naturally outgrow their allergy would yield the most benefit for health care resources and research funding,” Peters said.
Dr. Sara Dever of Allergy & Asthma Care comments: "We've long known that the majority of children with egg allergy will "outgrow" their allergy, but this shows that almost all do so by age 6, which is very reassuring. Prior studies have found that about 20% of peanut allergies resolve, so this is encouraging data that nearly 30% of young children with peanut allergy will "outgrow" this allergy. Correlation with eczema, other food allergies, and skin test size are helpful in deciding who may be a candidate for oral immunotherapy / desensitization to peanut and/or egg."