Age and Eczema Severity, but Not Family History, Are Major Risk Factors for Peanut Allergy in Infancy

Abstract

Since the publication of the Learning Early About Peanut Allergy (LEAP) study in 2015 and the addendum guidelines for the prevention of peanut allergy in 2017, there has been controversy regarding the need and value of performing screening tests in infants at a high risk of developing peanut allergy.In the study, the researchers included 321 infants aged 4 to 11 months with no history of peanut ingestion, testing, or reaction and at least 1 of the following risk factors for the development of peanut allergy: moderate to severe eczema, another food allergy, and/or a first-degree relative with peanut allergy.After a careful history regarding risk factors and a physical examination focused on eczema severity, the infants underwent peanut skin-prick testing and, depending on the skin-prick test wheal size, a graded oral peanut challenge or an observed feeding with a full serving of peanut.The median age of the participants was 7.2 months, and 58% were boys. A total of 78 had eczema only, 11 had other food allergies only, 107 had a family history only, and 125 had multiple risk factors. Overall, 37 (11%) were found to have a peanut allergy, including 18% of 195 with eczema, 19% of 59 with other food allergies, and 4% of 201 with a family history. Only 1% of 115 with a family history and no eczema had a peanut allergy. Among those with eczema, older age (odds ratio [OR]: 1.3; 95% confidence interval [CI]: 1.04 to 1.68 per month), higher severity of atopic dermatitis (OR: 1.19; 95% CI: 1.06 to 1.34 per 5 points on the Scoring Atopic Dermatitis), Black (OR: 5.79; 95% CI: 1.92 to 17.4, compared with White), or Asian American race (OR: 6.98; 95% CI: 1.92 to 25.44) and suspected or diagnosed other food allergy (OR: 3.98; 95% CI: 1.62 to 9.80) were associated with peanut allergy.In the study, researchers found that peanut allergy is common in infants with moderate to severe eczema and/or a history of other food allergies, whereas family without eczema is not a major risk factor. This strongly suggests that there is value in screening those with significant eczema and/or other food allergies. Even within the first year of life, introduction at later ages is associated with a higher risk of peanut allergy among those with eczema, supporting introduction of peanut as early as possible.With this study, the authors provide new and valuable information on an important and timely topic. First, there is value in screening infants at high risk, especially those with severe eczema with or without other food allergies. Second, as was suggested by the LEAP study, earlier introduction appears to be important for these infants at the highest risk. The window of protection may truly be closing by 6 to 7 months of age. Third, and one of the most common questions encountered in day to day practice, family history of peanut allergy without other risk factors does not impart increased risk, providing reassurance that those infants to do need to be tested before peanut introduction.