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Preventing peanut allergy

Consumption of a peanut-containing snack by infants who are at high-risk for developing peanut allergy prevents the subsequent development of allergy, according to Dr. Paul Hunt, a pediatrician and allergist, who cited the LEAP (learning early about peanut allergy) Study led by Professor Gideon Lack at Kings College London which was the first randomized trial to prevent food allergy in a large cohort of high-risk infants.

Hunt said the new guidelines based on the study published in the New England Medical Journal in February 26, 2015 is that if children with the highest risk of developing a peanut allergy are introduced to peanuts early, there is a great chance they would be prevented from developing a peanut allergy.

“This is monumental, because up until 2008-2010, the prevailing wisdom was [to] avoid peanuts or allergy-containing foods for the first two or three years of a child’s life. By 2008, we decided that didn’t seem to be working. An ounce of prevention is worth better than a pound of cure,” said the doctor at the recent Doctors Hospital Distinguished Lecture Series.

After the LEAP Study published its findings, Hunt said all of the allergists societies worldwide came together on the findings and in 2017 proposed the new guidelines to try and prevent peanut allergy.

Hunt said the LEAP Study is especially exciting to him and allergists worldwide, as since the 1990s, there has been a two-to-three-fold increase in peanut and food allergies in the last decade, including in places like Asia and Africa, where they did not have food allergies.

“We live in a world where there are gazillions of microorganisms – viruses, bacterial fungi, and they only have one intent, to turn us into pulp so they can basically feed on our bodies; they want to kill us.”

The immune system identifies a virus and mounts an immune response.

According to the doctor, a person’s immune system is their protection, but when the immune system doesn’t do what it should do, an allergy, he said, is basically a sort of malfunction of the immune system. He said it is a normal immune response, but it is triggered by an inappropriate stimulus.

Allergy or sensitivity

According to the doctor, peanuts are not supposed to be dangerous, but when a person eats peanuts, the body perceives that the peanut is dangerous, hence the allergic reaction.

“For reasons we don’t know, the body perceives that the peanut is dangerous, and does what the immune system does and tries to destroy it.”

Reactions include swollen face, vomiting and breaking out in hives.

“The only thing is it is being triggered by something that should not trigger it. So, when you have the immune system doing what it’s supposed to do for something it really isn’t designed to do, that’s what an allergy is.”

There are two ways to test if a child has a peanut allergy. Doctors can look for a peanut-specific antibody in the blood, or a skin test. If the results return positive, Hunt said they can determine the patient makes the antibody, and as such would be sensitive.

“When we test for antibodies for whatever substance, we say that the person is sensitive.”

And that, in most instances, he said if he tested a room full of people, he was almost positive one or two people would test positive for peanuts, even though they would have been eating peanuts and have no problems.

“In that instance where we test you and you have the positive antibody, then you’re sensitive. What makes you allergic, is in addition to having that positive antibody, if you have a problem when you eat the substance, or get exposed, and you have a reaction – that’s an allergy.”

Hunt said there are a lot of people, who if they test would have a positive result, but that it does not mean they are allergic.

The doctor said in many instances he has seen a parent come in and say they have a child who has an allergy, and want everyone in their family tested even though they did not notice any problems with anyone else. He said that’s usually not good.

“Sometimes there’s a lot of confusion, because in people’s mind, if the test results come back positive, a lot of people think the person may be allergic when in fact they’re not. Sensitivity just means you have a positive result. Allergies mean you have the positive result and you have a bad problem when you get exposed to whatever you had.”

When a person has an allergic reaction, he said, they itch, swell and cough. He said that’s a true allergic reaction.

When Hunt graduated from his allergy training in 1990, and even then, while he was in his fellowship, almost three decades ago, he said they knew people had food allergies, but that in comparison to today, a lot more people have food allergies in general. And he said food allergies have been increasing in the western world, and that they don’t know why.

Peanut concerns

According to the doctor, one of the problems is if you develop a peanut allergy, it’s permanent. He also spoke to the psychological effect it has on families with children with peanut allergy, especially knowing a peanut allergy is potentially fatal.

“It creates a lot of anxiety and psychological problems inside the family. You’re concerned when they’re in school they may come in contact with peanuts. A lot of people who have kids with peanut allergies don’t go on vacations; they don’t send their kids to parties; they certainly don’t want to send them to sleepouts. They have this big fear that something bad can happen, especially if they’re not around.”

He further said peanuts or other nuts which figure prominently on health guidelines to keep the heart healthy are excluded from the person’s diet.

According to the doctor, it was once thought that once a person had a peanut allergy they would never outgrow it, but that it wasn’t entirely true. He said 80 to 95 percent of children who develop a peanut allergy will have it for the rest of their life, and maybe 15 to 20 percent of them may outgrow it.

Peanut allergy prevention

During his training days, and up to 2008-2010, the doctor said the guidelines from the American, Canadian and British allergists recommended parents not introduce their children to high allergic foods during the first two to three years of life. He said they further instructed mothers not to consume the foods during pregnancy, nor when breastfeeding. But even while doling out this advice, the doctor said the incidence of peanut allergy and food allergy just kept increasing in the western world.

But the article by Lack made an important observation – he compared Jewish children living in England to Jewish children living in Israel; the Jewish children living in England had peanut allergies 10-times greater than the children living in Israel even though they had the same type of children same type of parents, and same heritage.

Hunt said that what showed most strikingly in the study was that in Israel, peanut-containing products were given to babies as early as five to seven months in the form of a peanut snack balled Bamba – especially when they were teething. The only difference between the two groups of children, he said, was that in Israel they were given peanuts quite early and in England, much later or not at all.

“As an allergist this is a very pivotal study. Essentially what the LEAP Study did is that they tried to identify kids who were at the highest risk for having peanut allergy. The kids who are at highest risk for developing peanut allergy have one or two preexisting things – they have bad eczema, and it starts quite early, or they have egg allergy, or in some kids they have both, and these things develop quite early, usually before the kids are three or four months old.”

In the LEAP Study a group of 640 children were enrolled for the study which was conducted between December 2009 and May 2013. When they started the study, Hunt said the children were four to 11 months of age, had severe eczema, or they had egg allergy or both. He said they were skin tested to see whether they were sensitive to peanut and that they weren’t allergic. They then split them into two groups – one sensitive to peanuts, one not sensitive to peanuts. In each group they did two things – one was given peanuts to eat and the other group had to avoid peanuts until they were age five. In the final result, Hunt said 542 were negative, 98 were positive, and the positive ones didn’t have peanut allergies, and that when they did the test it came up positive. In the group, he said, 270 children ate peanuts, and 270 did not eat peanuts.

At the end of the study, (617 children completed – some had dropped out for other reasons) he said all children were tested to see if they had peanut allergies. The results showed that in the people who, when the study started, skin tested negative for no antibodies to peanuts and followed up to age five in the group that didn’t eat peanuts – 13.7 of them developed peanut allergy. What he said was more intriguing was in the group that had peanuts, only 1.9 percent developed peanut allergy. 

“This was a huge result, because basically what it translates to is that if you got kids who were young, who did not have any peanut sensitivity and you fed them peanuts, there was an 86 percent chance that they would not develop peanut allergies and that is huge. In the avoidance group 35.3 developed peanut allergy compared to only 10.6 in the group that basically ate peanuts. This basically translates into, if you had a young child who had bad skin eczema, already had egg allergy, and if you were able to give those kids peanuts early, there was a 70 percent chance that they would not develop peanut allergy.”

Prevention guidelines

Due to the evidence-based data, Hunt said three recommendations were made. Children who have bad eczema, egg allergy or both, and are at the highest risk for having peanut allergy, he said a blood test or skin test should be done on them to see if they have a problem with peanut, and based on the result an oral food challenge could be conducted to see if they would react. If the child does not react, he said they should be fed peanuts quite early – between the ages of four to six months.

If a child has mild to moderate eczema, parents can introduce peanut-containing foods around age six months. And if a child has no eczema or any food allergy, he said peanuts can be introduced whenever a parent wants to; he said they recommend around seven to nine months.

The lone allergist in the country, and with the knowledge that not everyone has access to an allergist, Hunt said the new guidelines allow for a family practitioner or pediatrician to order a peanut specific test to see if a baby is sensitive to peanuts.

 

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