Peanut allergy affects around one in 30 children (that’s one child in each school class). We think that the rates of peanut allergy have probably stabilised – which means that while it shouldn’t become more common, there are still plenty people out there with peanut allergy, and a real need to help those children and their families affected. One recent advance is that we are now learning more on how to avoid peanut allergy developing in the first place. The LEAP study was recently published by the team at St Thomas’ Hospital, lead by Prof Gideon Lack. They found that up to 80% of peanut allergy could be prevented if infants are given peanut (as peanut butter or peanut snacks ie. not whole peanut, which they might choke on) by 6-12 months of age. We think exposure at this age might ‘train’ the immune system to tolerate the proteins in peanut and not treat them as something which needs to be fought off by an immune reaction.
But what can we do for those children who have already developed peanut allergies? These kids can have severe reactions to tiny quantities of peanut in food or even in their environment, and the outcomes are very unpredictable.
At St Mary’s, we are looking into ways to desensitize children over age eight years who have moderate to severe peanut allergy. We are coming to the end of our first year of the trial, with another 2 years to go. At the moment, very few kids have access to desensitization therapy, which is only available on a private patient basis at one other UK centre. The process involves slow and gradual exposure to tiny – milligram – amounts of peanut over months, which trains the body to get used to the protein. However, the peanut powder is now being licensed as a drug in the USA, which is going to increase the cost of the treatment: it is unlikely to be offered within the NHS for now.
At St Mary’s, we are testing a new approach, using a cheaper, low-tech solution where we use heat-treat the peanuts to make them less allergenic. However, there is enough peanut protein left to desensitize the person, but not enough to cause a reaction. We are finding this is very effective and so far, our safety data is looking very promising. Allergic reactions are still possible, so we have lots of safeguards in place; our visits all happen on a dedicated research unit where we are used to managing high-risk allergic reactions, with intensive care back-up right next door. One of the less pleasant aspects of the trial is that we have to prove the young people taking part are actually allergic in the first place. This means they have to come in first to eat a peanut in a carefully controlled way with us at the start. Some of the participants will only have a mild reaction, but some will develop severe symptoms such as breathing difficulties. This can be scary for them but there is a positive side too. Even if they have a serious reaction, we can swiftly bring it under control by using an adrenaline injection (e.g. Epipen). This is very reassuring, because they have the experience of having a bad reaction in a safe environment, know that the ‘pen’ doesn’t hurt and that the meds inside really work; their parents are also more confident that if their child was to have an anaphylactic reaction outside hospital, they can manage the situation and even that their child can use the ‘pen’ themselves.
The trial is going very well. Two participants who were very allergic at the start are now munching peanuts daily without a problem. There are lots of tears on the way but the results speak for themselves. It has been an amazing transition and I feel privileged to be part of it.