The LEAP study: 18 months later, putting evidence into practice

Nine month old Colton was trying scrambled eggs for the second timecolton-9-2016-compressor.  He had enjoyed eggs the first time he had tried them, but his mother noticed a rash on his face and around his eyes shortly after he begin eating the eggs.  Within minutes, Colton developed swelling of his eyes and began rubbing them.  Did this mean he was allergic to eggs?  What would it mean for other food allergies?  Would he be at risk for a peanut allergy as well?

On February 26, 2015, Dr. Gideon Lack of the King’s College London and his colleagues published the first data from a landmark study on peanut allergy in the New England Journal of Medicine.  The data came from the highly anticipated Learning Early About Peanut (LEAP) study and offered proof that early introduction of peanuts may offer protection from the development of peanut allergies.

Lack and the LEAP study team randomly assigned 640 infants with severe eczema, egg allergy, or both, to either consume or avoid peanuts until 60 months (5 years) of age. Additional clusters were identified in the cohort: children with sensitivity to peanut extract and children without sensitivity (as determined by skin prick tests).

Remarkably, the overall prevalence of peanut allergy in the peanut-avoidance group was 17.2% compared to only 3.2% in the consumption group. The prevalence of peanut allergies in children with negative skin prick tests early in life was at 13.7% in the avoidance group and 1.9% in the consumption group. Similarly, children already sensitive to peanuts reflected a 35.3% prevalence of peanut allergy in the avoidance group, compared to only 10.6% in the consumption group.

“Early consumption is effective not only in high-risk infants who show no sensitivity to peanuts early on, but it is also effective in infants who already demonstrate peanut sensitivity,” first author George DuToit, MB, BCh, also from Kings College London explained.

Overall the LEAP study demonstrated that the early introduction of peanut dramatically decreased the risk of developing a peanut allergy by 70-80% in the selected patient population.

Using the results from this study, allergists have been able to integrate this new evidence-based medicine into practice.  One of our allergist, Dr. Word, recently saw 9 month Colton as a new patient visit.  Colton had a history of mild eczema, but had recently been introduced to scrambled egg followed by symptoms concerning for an allergic reaction.  Skin testing in clinic showed that Colton did have an egg allergy.

Given that history, he would be at increased risk to develop a peanut allergy.  However, Colton also had skin prick testing to peanut at his visit, which was negative.  He was brought back to clinic within the month for an open oral challenge to peanut.

Since he was young, peanut powder was used and mixed with yogurt.  Colton was given increasing doses of peanut every 30 minutes under close observation.  Since Colton did not have any adverse symptoms with peanut consumption, he was instructed to start eating it regularly in his diet, 2-3 times per week.  The goal of this intervention was to prevent Colton from developing a peanut allergy later in life.

For parents with concerns about their child’s specific risk and recommended course of action, they should speak to a board certified allergist at Charleston Allergy & Asthma to discuss this further. We have a protocol at Charleston Allergy & Asthma based on the LEAP study to evaluate infants for possible peanut allergy and which can help to safely introduce peanut products into the diets of appropriate at risk infants.

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