Among parents of allergic children, peanuts are often experienced as a permanent threat. Peanut allergy affects approximately 2% of the population in Western Europe and North America and, in France, approximately one person in 100. The disease most often lasts throughout life and the risk of anaphylaxis requires constant vigilance. In Sweden, the National Board of Health and Welfare has been recommending since April 2026 to offer more treatments capable of changing this trajectory, includingOral peanut immunotherapy, which involves desensitizing the immune system to peanut through regular exposure.
How Oral Peanut Immunotherapy Works in Toddlers
It is in this context that researchers from the Karolinska Institutet conducted the SMACHO study involving 75 children aged 1 to 3 years presenting a peanut allergy of varying intensity (ranging from mild symptoms to severe allergic reactions after ingestion). Fifty of these children received active treatment in the form of oral immunotherapy based on peanut flakes, while the other 25, constituting the control group, avoided peanuts entirely.
The principle is to give a tiny amount of peanut each day, then increase very gradually. In SMACHO, treatment begins in the hospital with a very low dose, then continues at home with BAMBA-type peanut puffs. Every four to six weeks, the dose is increased to a maintenance dose equivalent to approximately one and a half peanuts per day, or 285 mg of peanut protein, taken for three years.
For Caroline Nilsson, who co-led the essay, “This is the first randomized study of oral immunotherapy in young children, with gradual dose escalation and low maintenance dose“. She adds that “The peanut cakes were easy to ingest, which simplified the treatment for families, and we were surprised by the positive results obtained.“. The objective is not to make the allergy disappear, but to significantly raise the reaction threshold, what researchers call a sustained tolerance.
What the SMACHO study from Karolinska Institutet shows
After three years of treatment then four to six weeks without peanuts, 82% of the treated children tolerated at least 750 mg of protein, the equivalent of approximately three and a half peanuts, compared to 12% in the exclusion group. Side effects occurred in 0.7% of doses and were mostly mild, such as “itchy mouth or rash.” A few children experienced severe reactions during dose escalation phases, including anaphylaxis, and received epinephrine.
Associate Professor at the Department of Clinical Sciences and Education at Södersjukhuset Hospital (Karolinska Institute) and senior consultant at the Sachs Children and Adolescent Hospital, Prof. Caroline Nilsson summarizes: “We consider this treatment to be safe if carried out under controlled conditions, within a healthcare establishment.“. His colleague Anna Asarnoj, associate professor at the Department of Women’s and Children’s Health at the Karolinska Institute, also warns that “This cautious approach to treatment appears to play an important role in safety, but it is not something parents should attempt at home, as serious reactions can still occur.“.
What does this mean for families of children with peanut allergies?
For a toddler who previously reacted to a few milligrams, being able to swallow several peanuts without symptoms clearly reduces the risk in the event of a menu error, a trace in a biscuit or contamination in a nursery. However, the child remains allergic and must keep his adrenaline pen, read the labels and avoid large quantities. After the study, the Swedish teams advised families to maintain at least one and a half peanuts three times a week in order to keep this tolerance high.
The authors from Karolinska Institutet recall that other trials of oral immunotherapy, often in older children with higher daily doses, have shown more adverse effects and more use of adrenaline. The “low dose and slow rise” approach in 1-3 year olds could offer a better compromise between effectiveness and safety. In Sweden, the new recommendations already encourage the controlled use of these treatments. In countries like France, this strategy remains reserved for specialized centers; for parents, the reflex to adopt is to talk about it with a pediatric allergist, and above all to never try peanut consumption alone, even in very small quantities.