Proper diagnosis of peanut allergy in children currently takes a two-day provocation test. PhD research by Hannah Kansen at UMC Utrecht shows that for some children a blood test is sufficient, for others a blood test and a one-day provocation test are sufficient. This is a considerably lower burden for the children and their parents and is a lot cheaper. These results will lead to an adjustment of the national guideline.

In the Netherlands, around 2,400 children are tested in a hospital each year because of a suspected peanut allergy. Peanut allergy has a big impact on everyday life, because children have to always watch what they eat. Peanut particles can be in many foods and tiny amounts of peanut can already cause severe allergic reactions. It is therefore very important to verify if a child has a peanut allergy, and to what extent.

To investigate such an allergy, a blood test is first performed to see if there are antibodies against the whole peanut in the blood. If that turns out to be the case, a two-day investigation will usually be performed. “In this study, a child is admitted to the hospital twice a day to eat peanut processed into gingerbread in ascending quantities, or a placebo: gingerbread without peanut. Children, parents, doctors and nurses do not know on which day the gingerbread with peanut is given. In this double-blind way of investigating, we switch off the placebo effect and we can very accurately determine whether there is an allergy and to what extent, ”says Hannah.

Results

In her research she looked at for which group such a two-day examination could be shorter or even not needed at all. For this she used a blood test that does not show whether there are antibodies against the whole peanut, but antibodies against a specific peanut protein. “If the blood test against this peanut protein shows that no antibodies are present, the risk is very small that there is an allergy. With these children, it is sufficient for the parents to carefully give their children peanuts in increasing quantities. Of course under the supervision of the hospital. They no longer need to visit the hospital for an examination. This applies to about 20 percent of children who take a blood test. Indeed, none of the children from this group studied by me turned out to be allergic to peanuts. "

However, if the blood test shows that there is a high level of antibodies present, according to Hannah it is almost certain that they are allergic. “It is not necessary for them to do the double-blind two-day study. It is enough to test in 1 day to what extent they are allergic. This applies to about 35 percent of children who take a blood test. For the group in-between - 45 percent - the two-day test remains necessary.”

Cost reduction

The intention is that the results of this study will be implemented in the treatment guideline. “If all hospitals start diagnosing in this way, many children and their parents will either not have to go to the hospital at all or just for one day. That saves them a lot of time and effort. Moreover, this will lead to national cost savings of up to EUR 1.5 million annually.”

PhD research

Hannah Kansen (1991, Hilversum) received her PhD on August 27, 2020 at Utrecht University. The title of her thesis was “Improving diagnostics and quality of life in children with peanut allergy and other atopic diseases”. Supervisors were prof. dr. Kors van der Ent (division Children, UMC Utrecht) and prof. dr. André Knulst (Department of Dermatology & Allergology, UMC Utrecht). Co-supervisors were dr. Francine van Erp and dr. Thuy-me Le (both Department of Dermatology & Allergology, UMC Utrecht). As of June 2020 Hannah Kansen works as a resident in pediatrics at Meander Medisch Centrum, Amersfoort.