Nut allergy study offers hope to families

Akira with his sister, Aaryan

New research carried out by Evelina London and Guy’s and St Thomas’ has found that children who were allergic to one type of nut could safely eat, on average, nine other types of nuts.

Peanut, tree nut and sesame allergies are responsible for most life-threatening food allergic reactions. The Pronuts study investigated whether, in a child with one type of nut allergy, other nuts could be introduced into their diet using a technique called ‘oral food challenge’ or OFC. This involves introducing different food types one by one under medical supervision.

As part of the study, children with an allergy to one type of nut were tested for their allergies to other types of nuts and sesame seed. They then underwent a series of ‘challenges’ with these nuts and sesame seed under strict observation.

Children were then asked to introduce the nuts that they were not allergic to regularly into their diet; which is part of the follow-up study for the Pronuts study.

Dr Helen Brough, consultant in paediatric allergy at Evelina London and Honorary Senior Lecturer at King’s College London, led the study. She said: “For children with a nut allergy, previous advice has been to cut out all other nuts from the diet and often also sesame seed. Our study shows that with a careful programme of introduction under medical supervision, parents of nut allergic children can find out exactly what nuts their children can eat safely and what nuts they are allergic to. By understanding a child’s nut allergies better, the programme ensures that their diet doesn’t need to be limited unnecessarily to avoiding all nuts and sesame seed.

“Parents need to be aware that the programme involves hospital visits and tests, and that the introduction of allergens happens under careful medical supervision. Parents of children with allergies should seek medical advice and shouldn’t try to replicate this programme at home.”

Rajesh Karimbath’s two children took part in the study. Akira, 5, and Aaryan, 10, both had nut allergies, however, since taking part in the Pronuts study, Akira’s cashew allergy has gone completely, while tests have confirmed Aaryan is only allergic to hazelnuts and pecans, and can eat all other types of nut safely.

Rajesh, 42, from Liverpool, said: “We were worried about Aaryan’s allergy and saw the research at Evelina London in the media. We contacted the hospital and came in for tests. It was a real surprise when we found out that in addition to Aaryan’s hazelnut and pecan allergy, Akira was allergic to cashews. That was a real issue as cashews are everywhere in south Asian cooking, so at family events or visiting family in India, we couldn’t be sure that she wouldn’t have a reaction. It was really scary that our children might be at risk like that from food, which is so central to our culture.

“Taking part in the Pronuts study was a glimmer of hope for us. It involved a lot of trips to the hospital, and required dedication, but as a parent it was incredible to get that education about how our children’s allergies worked. Even though the tests often involved needles, the kids weren’t worried about coming into Evelina London because the environment was so welcoming and the staff were so good with them.

“Three years later, Akira’s cashew nut allergy is gone, and it’s such a relief. Aaryan is still allergic to hazelnuts and pecans, but the testing has assured us that he is safe and doesn’t need to be afraid of other nuts. It means they can join in with family festivities and food, without us worrying about them.”

Dr Brough said: “It’s great that the results of the programme have been so positive for the Karimbath family. We’ve seen the same great outcomes for many other families, where limits to children’s diets can cause anxiety for the whole family. However, this should not be done without medical supervision, as some children did have severe reactions to the oral food challenges, and required treatment with adrenaline.”

The results of the Pronuts study are published in the Journal of Allergy and Clinical Immunology. In addition to showing that children with one nut allergy can safely eat, on average, nine other nut types, it shows that 60% of children with one nut allergy will have another, and that certain nut allergies are more commonly grouped together. The study was part of a wider programme of work at Evelina London to understand how best to treat and even prevent children’s allergies.

The Pronuts study is co-sponsored by King's College London and Guy’s and St Thomas’. Food Allergy Research and Education (FARE) provided funding for the Evelina London arm of the study, the Ulrich Muller-Gierock Foundation provided funding for the Geneva arm of the study. ThermoScientific, Stallergenes and Meridian Foods provided research supplies for all centres.