Prevention of Peanut Allergies: Are We Ready to Take the LEAP?
By now, every family living with peanut or food allergies has heard about the landmark study findings released on February 23, 2015. I happened to be in attendance at the American Academy of Allergy, Asthma and Immunology meeting when the authors disclosed the findings of the Learning About Peanut Allergy (LEAP) study. I have never seen such buzz and excitement from within our field!
As with all research findings, it’s important to read past the headlines. We have known for some time that rates of food allergy have increased dramatically in recent years with no currently effective treatment other than strict avoidance. This requires significant lifestyle modification and vigilance, which can impact quality of life.
Recent research has mostly focused on possible treatment of children who already have food allergy (stay tuned for my next blog post), but this hasn’t been as successful as once hoped. However, the LEAP study was about prevention, NOT treatment of children who already have peanut allergy.
There has been much confusion and debate about when young children should eat highly allergenic foods. In 2000, the American Academy of Pediatrics recommended no peanuts, tree nuts, or seafood until 3 years of age. Just 8 years later, they released updated guidelines stating that there was insufficient evidence to recommend avoidance of any specific food to prevent the onset of allergic conditions. Needless to say, the confusion regarding these conflicting messages still resonates with pediatricians and parents today.
With the LEAP study, we finally have some proof that early introduction may prevent against the development of peanut allergies. Before I summarize the important findings, it is extremely important to realize that this should NOT be done at home in high risk infants! Every single child enrolled in this study underwent skin prick testing AND physician supervised oral challenge to peanut. 10% were deemed too risky to proceed and 13% had reactions during challenge.
The LEAP study included 640 infants, all 4-11 months of age who were separated into those with negative skin tests and those with mildly positive skin tests (1-4 mm wheal; sensitized but not allergic). These groups were randomized to either eat peanut (roughly 8 peanuts per serving) 3 times a week or completely avoid all peanut until 5 years of age. At 5 years, they all underwent repeat peanut oral challenges to determine allergy.
The results are amazing! Children with negative skin tests who ate peanut were 86% less likely to have peanut allergy compared with those who avoided. Those who had mildly positive skin tests were 70% less likely to have peanut allergy. This demonstrates both primary and secondary prevention of development of peanut allergy. While this may not help those living with peanut allergy today, it may offer ways to prevent this for countless others.
It is important to note that this was not 100% effective. 2% of those with negative skin tests and 11% of those with mildly positive skin tests went on to develop peanut allergy. In addition, infants were chosen very carefully and had to have severe eczema and/or egg allergy to participate. We must be careful before extrapolating these findings to other populations.
Next steps for myself and my allergy colleagues around the world are to figure out how to apply these results in our practice. Infants at high risk of developing peanut allergy must be carefully evaluated before this is attempted. However, infants at low risk should proceed as recommended in 2008 and incorporate peanut butter early in life (6-12 months). This is certainly one exciting LEAP for us all!
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