Until now, a proper diagnosis of a peanut allergy in children requires a two-day provocation test. PhD research by Hannah Kansen at UMC Utrecht shows that for some of the children a blood test is sufficient and for others a blood test and a one-day provocation test is enough. This is a considerably smaller burden for the children and their parents and much cheaper. These results will lead to an adjustment of the national guideline.

In the Netherlands, about 2400 children a year are tested in hospital on suspicion of a peanut allergy. This allergy has a great impact on daily life, because children constantly have to pay attention to what they eat. Peanut traces can be found in al lot of foods and even a small amount of them can cause a severe allergic reaction. It is therefore very important to know for certain that a child has a peanut allergy and to what extent.

To determine such an allergy, a blood test is done to see if there are antibodies against the whole peanut in the blood. If that turns out to be the case, a two-day examination is common. "In this study, a child is hospitalized two days to eat peanut processed in cake in increasing amounts, or eat a placebo: the cake without peanut. Children, parents, doctors and nurses do not know on which day the cake with peanut is given. In this double-blind method of research, we eliminate the placebo effect and can determine very accurately whether there is an allergy and to what extent," says Hannah.

Results
In her research, Hannah looks at what group could have a shorter test or even do without it at all. For this she used a blood test that does not show whether antibodies to the whole peanut are present, but antibodies to a specific peanut protein. "If this blood test against this peanut protein shows that there are no antibodies present, the chance that there is an allergy is very small. For these children, it is sufficient that the parents give their children peanut carefully in increasing amounts. Under the supervision of the hospital off course. They no longer need to go to the hospital for examination. This applies to about twenty percent of the children who take a blood test. None of the children I examined from this group turned out to be allergic to peanuts."

However, if the blood test shows that there are many antibodies present, it is virtually certain that they are allergic. "For them, it is not necessary to do the double-blind two-day study. It is sufficient to test in one day to what extent they are allergic. This applies to about 35 percent of the children who take a blood test. For the group in between - 45 percent - the two-day examination remains necessary."

Saving Costs
The intention is to incorporate the results of this study into the treatment guideline. "If all hospitals start diagnosing in this way, many children and their parents will either not have to visit the hospital at all or only for one day. That will save them a lot of time and effort. Moreover, nationwide this will lead to cost savings of up to one and a half million euros per year."

PhD research
Hannah Kansen (1991, Hilversum) received her doctoral degree on August 27, 2020 from Utrecht University. The title of her dissertation was "Improving diagnostics and quality of life in children with peanut allergy and other atopic diseases". Supervisors Prof. Kors van der Ent (Division of Children, UMC Utrecht) and Prof. Dr. André Knulst (Afd. Dermatology & Allergology, UMC Utrecht). Co-supervisors Dr. Francine van Erp and Dr. Thuy-me Le (both Dep. Dermatology & Allergology, UMC Utrecht). Hannah Kansen is being trained as pediatrician (Meander Medisch Centrum, Amersfoort) since June 2020.