Peanut allergy is an important public health concern and causes substantial psychosocial comorbidity. Although fatal anaphylaxis is rare (occurring at 0·03-0·3 per million person-years in the general population), peanuts are one of the most frequent causes of food allergy mortality. The Learning Early About Peanut study transformed prevention of peanut allergy by showing that early introduction of peanut into the diet of children at high risk (ie, those with an egg allergy or severe eczema) reduced the relative risk of peanut allergy at age 5 years by 81%. Following publication of this study, the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, convened an expert panel, which recommended that, for infants with severe eczema or egg allergy, health professionals should strongly consider evaluation with peanut-specific serological IgE or skin prick test (or both) and, if necessary, an oral food challenge before peanut introduction. In the USA, depending on test results, peanut-containing foods are recommended to be introduced from age 4-6 months in infants with severe eczema or egg allergy. Early introduction to peanuts is also advocated for children with either mild to moderate or no eczema, and in children who are not allergic to egg, but without screening before peanut introduction. However, the NIAID addendum guidelines contrast with other international approaches that do not advocate for allergy screening at a population level before introducing peanuts into infants’ diets. In this Review, we evaluate the advantages and disadvantages of a pre-emptive screening approach before the early introduction of peanuts in infants at high risk of peanut allergy.Copyright © 2020 Elsevier Ltd. All rights reserved.