For years, the focus of food allergy research has been on peanut allergy. That’s because peanut allergy has been one of the most common food allergens and serious reactions have more frequently been connected to peanuts. Adding to this, most kids don’t outgrow peanut allergy so it made sense to start with peanut. Fast forward to today, and we have many options to support children and adults with peanut allergies. We have Palforzia as the first approved oral immunotherapy (OIT) for peanut allergy; ongoing research in sublingual immunotherapy (SLIT), epicutaneous immunotherapy (EPIT), and peptide immunotherapy focused on peanut allergy. Plus, the recent approval of the biologic Xolair (omalizumab) whose data was anchored on peanut allergy. We have also seen the remarkable data from the LEAP study by George Du Toit (GrowHappy co-creator) and Gideon Lack that showed us that we can prevent peanut allergy with early introduction, which is the scientific basis behind the GrowHappy line of products.
This early work has shown us that we can make a difference. We have ways to prevent peanut allergy, and if we don’t succeed at preventing it, we have ways that we can treat it. But we know many folks are allergic to much more than just peanut with an estimated 50% of patients being allergic to multiple foods. It's time to take what we have learned from peanut as the model allergy and move to the other foods that people might be allergic to.
If you ask allergists in the US, Australia, and the UK, top on the list of food allergy priorities today is likely to be cashew. Cashew allergy has similarities to peanut, being prone to more serious reactions even with low level testing and small exposures and is likely life-long for most patients. Furthermore, it seems to be increasing in frequency. Maybe it's because we are no longer lumping tree nuts together but looking at each specific nut in clinics, or possibly because of the availability of many more cashew containing products in stores. Data from the Australian HealthNuts and EarlyNuts birth cohorts have shown rates of cashew allergy highest among the tree nuts and approaching the level of peanut allergy. In the US, cashew was the most common tree nut in the OUTMATCH multi-food allergy study, and patients with cashew allergy had the lowest thresholds of all the tested foods. That means that a small amount of cashew can cause a serious reaction. In the UK, analysis of the European Anaphylaxis Registry from 2007-2024 showed that cashew was the most common cause of tree nut anaphylaxis.
There is some good news too. Recent data from the HealthNuts birth cohort showed that no children that ate cashew before age 1 year was diagnosed with cashew allergy at age 6 years. For patients that already have cashew allergy, the Nut CRACKER study showed that food-based OIT can be very successful at desensitization treatment and a study of sublingual immunotherapy for cashew is currently in the works. And of course biologics bring the promise of treating multiple food allergies at the same time.
Cashew allergy is rapidly rising to the forefront, but leaning on what we have learned from peanut allergy, we have ways to prevent it and we have ways that we can treat it. Together we can make a difference.
