Controlled peanut intake may reduce allergies in toddlers, finds study

Researchers at Karolinska Institutet have successfully treated children aged 1-3 years with peanut allergies. The children slowly became accustomed to eating peanuts by consuming small amounts of them daily, which were gradually increased over time. The results are presented in The Lancet Regional Health - Europe.

“All children who followed the protocol achieved the goal of eating three and a half peanuts without experiencing an allergic reaction, and most were able to consume up to 25 peanuts,” says Caroline Nilsson, associate professor at the Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, and senior consultant at Sachs' Children and Youth Hospital. “We consider the treatment to be safe if it is carried out under controlled conditions in a healthcare setting.”

Peanut allergy is often lifelong and can lead to constant worry about severe allergic reactions. In April 2026, the Swedish National Board of Health and Welfare presented new allergy care guidelines, recommending that more patients be offered treatments that can alter the course of the disease. This includes oral immunotherapy for children with severe peanut allergies, whereby the immune system is desensitised to peanuts through regular exposure.

Treatment began in hospital with a very low dose and was then continued at home with daily intake. Every four to six weeks, the dose was increased until the children reached a low maintenance dose equivalent to approximately 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,” says Caroline Nilsson. “The peanut puffs were easily ingested, which made the treatment simple for families to follow, and we were surprised by how positive the results were.”

After three years of treatment, 82 per cent of children in the treatment group could eat at least three and a half peanuts without having an allergic reaction, even after taking a four-week break from the treatment. By comparison, only 12 per cent of children in the control group could tolerate such quantities.

Side effects occurred but were mild in most cases, such as itching in the mouth or skin rashes. More serious reactions mainly occurred during dose‑escalation periods, and a few treated children required an adrenaline injection to treat a severe allergic reaction.

The researchers emphasise that treatment must always take place under controlled conditions, in close contact with healthcare professionals and with medical follow-up.

“The cautious treatment approach appears to play an important role in safety, but this is not something that parents should attempt at home, as serious reactions can still occur,” says Anna Asarnoj, associate professor at the Department of Women’s and Children’s Health, Karolinska Institutet, and senior consultant at Astrid Lindgren Children’s Hospital, Karolinska University Hospital, who led the study together with Caroline Nilsson.

The next step is to analyse how the immune system changes during treatment, and to observe the children over a longer period to determine whether tolerance persists.

The children were identified via the Karolinska University Hospital laboratory, which analyses samples from various levels of care. They were then treated at the research unit at Sachs' Children and Youth Hospital, Södersjukhuset, in Stockholm. The research was funded by a private donation, Region Stockholm (ALF funds) and the Swedish Asthma and Allergy Association. Some of the paper’s authors state that they have received fees from pharmaceutical companies, but these are unrelated to the current study.'

Reference:

Susanna Klevebroa, Carina Uhla, Jon Roald Konradsenc, Josefin Ullbergc, Sandra Ganrud Tednerc, Idun Holmdahla, Isabella Badolatif, Rui Da Silva Rodriguesg, Eva Sverremark-Ekströmf, Caroline Nilssona, Anna Asarnoj, Safety and efficiency of peanut oral immunotherapy in preschool children with slow up-dosing and low maintenance dosing: a randomised controlled trial, Journal: The Lancet Regional Health - Europe, DOI: 10.1016/j.lanepe.2026.101690.