Researchers at the Karolinska Institutet have reported promising results from a long-term peanut oral immunotherapy (OIT) study involving toddlers with peanut allergy. Published in The Lancet Regional Health – Europe, the study focused on children aged 1–3 years, a period when the immune system may be especially adaptable. By gradually introducing increasing amounts of peanut protein over several years, researchers were able to significantly raise many children’s tolerance to peanuts under carefully supervised medical conditions.
The randomized clinical trial involved 75 children in Stockholm, Sweden, with confirmed peanut allergies ranging from mild to severe. Fifty children received oral immunotherapy using peanut puffs, while 25 children in a control group continued strict peanut avoidance. Treatment began in a hospital setting with extremely small doses before transitioning to daily dosing at home. Every four to six weeks, the dose was gradually increased until participants reached a maintenance dose equivalent to about one and a half peanuts per day.
“This is the first randomised study of oral immunotherapy in toddlers involving a slow up-dosing and a low maintenance dose,” said Caroline Nilsson, associate professor at Karolinska Institutet. She added that the peanut puffs were easy for young children to eat, making the regimen “simple for families to follow.”
After three years of treatment, 82 percent of children in the treatment group could consume at least three and a half peanuts without an allergic reaction, even after taking a four-week break from therapy. By comparison, only 12 percent of children in the peanut-avoidance group achieved similar tolerance. Researchers also noted that all children who successfully followed the protocol reached the study’s target tolerance level, and most were able to consume up to 25 peanuts safely.
Safety remained a central concern throughout the study. Most side effects were mild, including mouth itching and skin rashes, though more serious reactions occasionally occurred during dose-escalation periods. A small number of children required epinephrine injections to treat severe allergic reactions. “The cautious treatment approach appears to play an important role in safety, but this is not something that parents should attempt at home,” warned Anna Asarnoj of Astrid Lindgren Children’s Hospital and Karolinska Institutet.
The findings arrive as Sweden introduces updated national allergy care guidelines encouraging broader use of treatments that may modify the course of allergic disease, including oral immunotherapy for severe peanut allergy. Researchers say the goal is not only to reduce reactions from accidental exposures but also to lessen the daily anxiety many families experience living with food allergies.
The team now plans to study how the immune system changes during treatment and to monitor participants over a longer period to determine how durable the tolerance remains over time.
