Successful Introduction of Peanut in Sensitized Infants With Reported Reactions at Home

Infants with a history of adverse reactions to peanut at home and demonstrated sensitization to peanut are often classified as peanut allergic. Previous studies have demonstrated the efficacy of early peanut introduction in prevention of peanut allergy. The current study sought to evaluate a diagnostic pathway for children with early parent-reported peanut reactions at home and evaluate the contribution of an open food challenge (OFC) in the diagnosis of peanut allergy.The PeanutNL cohort includes 892 Dutch high-risk infants referred to pediatric allergy centers between 4 and 12 months. Seven hundred six of these patients had never eaten peanut and were referred for clinical peanut introduction. A subgroup of 186 infants had previously experienced reactions to peanut with the first introduction at home and were referred for analysis and advice regarding peanut ingestion. The 186 infants with prior peanut reactions had a median age of 8 months, and 89% had atopic dermatitis with a median SCORAD of 28. Eighty-eight percent of the studied infants had a first-degree family member with atopic disease, and 12% had a first-degree relative with a peanut or nut allergy.All 186 patients with prior peanut reactions underwent peanut skin prick testing. Twenty-three were not challenged due to parental refusal or severity of initial adverse reaction. Of the 163 challenged patients, 120 had a negative OFC with a cumulative dose of 4.4 g of peanut protein. Of the 120 patients with a negative OFC, 50 had negative skin prick tests and 70 had positive skin prick tests to peanut. After a negative OFC, peanut was introduced at home.Sensitization to peanut was detected in 69% of the 186 infants. Eighty percent had greater-than-4-mm wheals on peanut skin prick tests. Skin prick tests were negative in 57 infants (31%), despite the history of a previous clinical reaction to peanut. After 6 months, follow-up data were available for 114 patients. Of the patients who introduced peanut, 96% were still eating peanut, and 81% were eating single portions of at least 3 g of peanut protein after 6 months.In 65% of the infants studied with reported home reactions to peanut, an OFC was negative. In children with negative OFCs, 96% introduced peanut safely and reported long-term tolerance. Challenging infants younger than 12 months prevents misdiagnosis of peanut allergy and allows continued exposure and induction of long-term tolerance.Interestingly, approximately one-third of the infants with reported reactions at home did not have peanut sensitization on skin testing, suggesting that mislabeling of symptoms is common. In many infants, systemic tolerance seems to be achievable by gastrointestinal exposure at a young age. The authors suggest that in the development of peanut allergy, there may be a pre-stage of local skin reactions. As the authors suggest, this would imply that evaluation and intervention in infancy increases opportunity for “secondary prevention” of peanut allergy and promotion of peanut tolerance.