RIGHT NOW, as I type, many of the world’s top and absolutely bestest allergists and allergy experts are gathered in Houston for the American Academy of Allergy, Asthma and Immunology annual meeting. Later tonight, the UK’s Professor Gideon Lack will reveal the data from the long-awaited LEAP (Learning Early About Peanut Allergy) study into how best to prevent peanut allergy in young children.
In the run-up, I have been following the tweets from the great and the good gathered at the conference and the most amazingly informative string of posts has just come through from Canadian allergist Dr David Fischer. He calls it a Twitter essay on LEAP. Genius, and I felt it was worth sharing so I’ve pasted it below. (If you want to follow Dr Fischer on Twitter he’s @IgECPD and if you want to follow the conference tweets search the hashtag #AAAAI15.)
‘How we got to the leap study and what’s at stake’: A Twitter Essay by David Fischer, MD
1. There are 2 known ways of inducing tolerance (ie preventing allergy) in children: high zone tolerance and low zone tolerance
2. The concept of low zone tolerance is that if you’re not exposed to something you can’t become sensitized/allergic to it
3. Concept explains why North Americans become allergic to animals they’re exposed to (cats/dogs) but not, say, Tasmanian Devils
4. Original theory behind strict avoidance of food allergy introduction until older ages in children based on low dose tolerance theory
5. High zone tolerance is when large early exposures induce tolerance. This is the plan of the LEAP study
6. The problem with the low zone tolerance idea in the West is that the strict avoidance of these foods is impossible
7. Most patients reacting to peanut have with 1st exposure, but it’s not their 1st. Traces in packaged food & skin exposure in homes problem
8. A few Physician groups put out warnings based on Strict Avoidance/Delayed Introduction. That timed with increase in food allergy rate
9. These Guidelines were reversed years ago, allowing for earlier introduction of foods to children…with the hope of it being preventative
10. An Aussie study has already shown that introducing cooked egg between 4-6 months of age appears to prevent sensitization to egg
11. Dr Lack (LEAP study author) has already noted that the rate of peanut allergy in Israel (where peanut is 1 of the 1st foods) is lower
12. Lack feels it’s a race against time to induce oral tolerance to peanut before intermittent trace exposures (esp skin) induce allergy
13. What we find out today is whether we can literally PREVENT peanut allergies through early peanut introduction. Stay tuned
Note: I asked him if he would mind clarifying ‘intermittent’ in this context and he replied: “From a food perspective I would mean small exposures such as feeding a child foods that have ‘traces of nuts’ instead of nuts.”
So there you have it. Now waiting on that LEAP* data.
* The LEAP trial took 640 children aged between four months and 11 months of age who were identified as high risk for peanut allergy (based on an existing egg allergy and/or severe eczema). They were randomly split into two groups – consumption or avoidance. Those in the consumption group were to consume a peanut-containing snack with three or more meals per week; those in the avoidance group were not to ingest peanut-containing foods, both until the age of five. Here is more on LEAP from the BSACI and the Anaphylaxis Campaign.
**UPDATE** And here we have it – feeding peanuts to young infants with heightened allergy risk dramatically reduces the odds that a peanut allergy will develop. Follow the links to the study findings in the New England Journal of Medicine, an article in the New England Journal of Medicine blog here, the Allergic Living report here and The Telegraph here. Worth noting that Professor Lack has stressed that infants showing early signs of peanut allergy (those with skin prick test reactions greater than 4mm) were excluded from the study and effects of peanut consumption in this group remain unknown. But this is properly groundbreaking stuff…