A new way to tackle peanut allergies
For children and the parents of children with peanut allergies, the world outside their home can seem like a scary place. Oftentimes, the whole family will give up all peanut products in an effort to make sure no accidental ingestion occurs at home. But it’s harder to control things in restaurants, at school or at social outings.
“We know that 50 percent of children with food allergy experience accidental ingestion within five years,” said allergist/immunologist John Johnson, DO, at the Allergy & Asthma Centers of Cape Cod in Yarmouth Port and Falmouth. “Seventy-five percent of those children will have an accidental ingestion within 10 years. It’s actually higher for peanut allergies specifically. Fifty percent of peanut allergic children will have accidental ingestion within two years. It’s through the roof and that’s what everyone is worried about.”
That concern is driving a change in how peanut allergies are treated by allergists statewide. Until recently, no allergists in Massachusetts did oral immunotherapy for peanut allergies (peanut OIT). Now, because of demand, everyone is jumping onboard. Patients and their parents simply want this treatment.
“Parents get frightened, especially as their children get older and are no longer under their direct supervision anymore,” Dr. Johnson said. “They’re hanging out at a friend’s house, or driving on their own, or heading off to college. Those are the times that everyone worries about.”
Dr. Johnson had just shy of two years’ experience with peanut OIT during his allergy fellowship in Cleveland, but when he arrived on the Cape in July 2018, no one was doing the procedure. But that is about to change.
“It’s kind of big news because across the board everyone in the state is going to start offering it,” he said. “The driving force behind peanut oral immunotherapy being offered now is to reduce the risk of a severe anaphylactic reaction and to give parents peace of mind.”
The lifetime prevalence of anaphylaxis is actually low, at just .05 to 2 percent, with death occurring in 0.65 of that small number, Dr. Johnson said, but no family wants to be in that unlucky percentage.
Not a Cure
Peanut oral immunotherapy is a not a cure. It is a desensitization procedure intended to prevent a severe allergic reaction in the case of accidental ingestion.
Dr. Johnson goes through a long fact sheet of all of the risks of the therapy with patients, including the fact that up to 15 percent of patients will not be able to successfully complete the treatment. Almost all patients who go through the therapy have a return of their peanut allergy within a few months of stopping it, so they will have to continue to eat a handful of peanuts every day for the rest of their life to maintain the protection.
“With allergy shots, which are the most effective and well-known desensitization procedure, we know there is a lasting benefit that means that people don’t need to get their shots for the rest of their life,” he said. “But with peanut OIT, we don’t know if people can ever stop. No one has studied it in the long run.”
During the treatment of peanut allergies, 80 to 90 percent of patients will have a mild reaction. Most often it is some abdominal pain, vomiting or itching around the mouth, but not anaphylaxis. Up to 10 percent of patients will have a reaction severe enough to require an epinephrine injection and those reactions usually occur at home and not the allergist’s office when they are under medical supervision.
Peanut oral immunotherapy is also very time-consuming. There are two parts to it: the build-up phase and the maintenance phase.
“During the build-up phase, it takes a minimum of 16 weekly or every other week office visits,” Dr. Johnson said. “The first office visit will take approximately four and a half hours and subsequent visits will take about 1 to 2 hours.”
That is four months of treatment if the patient goes every week and twice as long if they opt for bi-weekly.
“Every time we do it in the office we actually increase the dosage and then at home they stay on that same dose,” he said. “They don’t increase the dose of peanuts at home. You start at a very low dose and increase gradually over time. We find the higher we push the final target dose, the better our patients do.”
Importance of Prevention
In addition to treating peanut allergies, Dr. Johnson also said that focusing on prevention is important. Expectant mothers should be encouraged to eat peanuts while pregnant and breastfeeding. Additionally, the American Academy of Pediatrics now recommends exposing children to the most common food allergies including peanuts between four and six months of age to hopefully prevent allergies from occuring.
One case in point is that peanut allergies are very rare in Israel. The prevailing theory about why that is true is that young children are commonly fed peanut butter puffed snacks called Bamba. A study published in The New England Journal of Medicine confirmed that theory. For the study, 640 infants were assigned to either avoid or consume peanuts until 60 months of age.
In the group of infants that initially had negative reactions on the skin prick allergy test, 13.7 percent of the ones who avoided peanut products had peanut allergies at the end of the trial, compared to 1.9 percent in the consumption group. In the group that has positive skin test results, 35.3 percent had allergies at 60 months, compared to 10.6 percent in the consumption group. The peanut food of choice for the study was the Bamba, which now can be found at Trader Joe’s in the United States.
Even though Dr. Johnson understands the fears that have created nut-free zones in schools and public places, he said that practice actually contributes to the problem of allergies.
“With allergies we know the less we are exposed to something at the right time, the more likely we are to become allergic to it,” he said. “There are a lot of peanut-free environments and so no kids can be exposed to peanuts, at least while they are at school or even at home, sometimes, if they have a friend who is allergic. Some kids have no peanut exposure and it’s leaving us wide open for additional peanut allergies.”