New studies point toward an earlier introduction to reduce risk
By Kathleen A. Sheerin, M.D.
Regardless of your specialty, there is breaking news you should be aware of: peanut allergy has become a nationwide problem affecting 1-3 percent of children. It is estimated that 1 in 50 school children have the diagnosis.
Peanut allergy incidence has skyrocketed in the last decade. No one knows why it has increased so rapidly, but growing evidence suggests that decades of delaying introduction of highly allergenic foods â€“ until children reach their second or third birthday â€“ could be a strong contributing factor.
The LEAP (Learning Early About Peanut) study was presented at the American Academy of Allergy Asthma and Immunology and published in The New England Journal of Medicine in February 2015. The study provides Level 1 evidence that early introduction of peanuts to children who are at risk of developing a peanut allergy may actually keep them from becoming allergic.
Doctors in the UK looked at a group of 640 infants, ages 4 to 11 months, who had severe eczema, egg allergy or both. They did skin prick testing to determine if the children were sensitized to peanut even though they had not started to eat it in their diet. Those who were allergic were eliminated from the study, while the others were divided into two groups â€“ one group with a negative skin test to peanut, the other with small reactions of less than 4mm.
The children either avoided peanut until 60 months or consumed peanut regularly. In the children who had negative results on the skin test, there was an astounding difference in peanut allergy at the end of the study: 1.9 percent of those who ate peanut regularly developed peanut allergy, as compared to 13.7 percent of those who avoided peanut. The risk reduction in this group was an impressive 80 percent. Results were similar in the group who had small skin test reactions, although numbers were higher: 10 percent in those who ate peanut vs 35 percent in those who avoided.
The conclusion is that early introduction of peanut, between 4 and 11 months, decreases the chance of developing a peanut allergy. This is very exciting news for parents of children with this food allergy. For years, the American Academy of Pediatrics recommended waiting until children were at least 3 years old to introduce peanuts. This recommendation was changed in 2000 because there was a lack of evidence or significant data to support it. Pediatricians and allergists have not been proactively starting children on a regular diet of peanut to prevent the development of allergy. This study, however, and an earlier one by the same group of scientists, suggest that an early introduction is the way to go.
Experts in the field of food allergy find the data so compelling that they are suggesting that any infant between the ages of 4 and 8 months who is believed to be at risk for peanut allergy should undergo a skin prick test for peanut.
If testing is negative, the child should be started on a diet that includes 2 grams of peanut three times a week for three years. This would be the equivalent of 6 teaspoons of peanut butter a week, which could be mixed into cereal. There are also peanut snacks available from Israel (trade name Bamba) that were used in the study. These are available online.
If children have minimal reactions on skin testing, they should undergo a food challenge in the allergist office. If they do not have a reaction, they should also start on the peanut prevention program. The study does not address siblings of children with food allergies or children with no obvious risk factors.
Many allergists would consider a sibling of a food allergic child at increased risk, and this allergist will follow the protocol for these children as well. I believe we, as physicians, should be actively advising parents to change the pattern of decades of traditionally not introducing foods early. The magic window seems to be between 4 and 11 months. If you wait, you may miss the chance.
The devil is often in the details. We still need to work out how much, how long and how often children should eat peanuts to avoid a lifelong allergy. The guidelines on how to introduce peanuts in the high-risk children, those with eczema and/or those already with other food allergies have not yet been formalized. These recommendations should be forthcoming from the NIAID Working Group.
The new recommendations may frighten some parents (and pediatricians). Board-certified allergists are equipped to help in this major transition in food introduction with testing and challenges in the office for high-risk children. The challenge to the parents is how to feed peanut products to their infants and toddlers, especially those with another child at home who is allergic to peanuts. Further study will need to address the early addition of other allergenic foods such as nuts, shellfish, fish and eggs.
Toit,GD, Randomized Trial of Peanut consumption in Infants at Risk for Peanut Allergy, N Engl J Med 2015; 372:803-813..This is the LEAP Study.