Peanut Allergies: A Q&A with an Allergist

A recent study in The Lancet found that oral immunotherapy effectively built up tolerance in children with peanut allergies to the point where they could safely eat about five peanuts. Though this was effective for 84 percent to 91 percent of participating children, researchers still cautioned that they were under medical supervision, and this should not be tried on your own.

In light of this research, we asked Dr. James Thompson, a board-certified allergist and asthma specialist, his take on oral immunotherapy, peanut allergy and more.

Why are peanut allergies so dangerous?

The first thing is that the cases of peanut allergy has tripled since 1997 in the U.S. and various other developed countries around the world. The second thing is that of all food allergies, those caused by peanut and shellfish are potentially the most fatal. More than half of the food allergy deaths in the U.S. have occurred because of peanut allergies, and for children, it’s upwards of 80 or 90 percent, because peanut allergies are more common among children.

Just the existence of peanut allergy can greatly affect a person’s quality of life in terms of making him or her feel anxious any time they eat something because peanuts can be hidden in many foods.

Why do you think there is a rise in peanut allergies?

There are only theories, and they have some evidence base behind them, but not solid scientific evidence.  One theory, called the hygiene hypothesis, is that the Western or developed lifestyle has less exposure to bacteria and various toxins, which has allowed our system to become more sensitized to things it shouldn’t be. There is some science developing to back that up in terms of white blood cells, T-lymphocytes in particular, in how they’re stimulated or they fail to be stimulated to go in one direction or the other.  One direction makes you more allergic, the other direction makes you more tolerant against infection.

So, the thinking is this more sanitized lifestyle we live in may have led to there being a subset of people in our population who are more allergic, as well as the use early on of antibiotics and vaccinations. Now, of course, the risk-benefit ratio of getting antibiotics for infections and vaccinations far outweigh the likelihood of developing allergies, but that perhaps is a reason for this evolving state of people being more hypersensitive.

What is oral immunotherapy?

Oral immunotherapy is where the patient is fed a very small amount of the particular allergen, usually mixed in with a safe food.  This allergen dose is increased gradually over time to boost tolerance.  But, there is more risk involved with oral immunotherapy than other types of immunotherapy.

Do you use it in your practice for food allergy?

In our practice, we limit immunotherapy to injection therapy and we don’t use any oral immunotherapy or sublingual immunotherapy.  Allergy shots are approved by the FDA and have very well-defined standards, and have been given since 1911. Whereas oral immunotherapy, although it does go back more than 70 or 80 years, was abandoned for a number of years because it not found to be as effective and to even be unsafe.  In the last 15 to 20 years it has reemerged, but it’s still not approved by the Food and Drug Administration (FDA) or European Medicines Agency.

What are the problems with oral immunotherapy?

One is that the effectiveness for tolerance has not yet been scientifically proven by enough studies. That means when you give someone oral immunotherapy, your goal is to make them more tolerant if they were to eat it or have contact with it. Well, to build up to an acceptable tolerance, that means for some period of time after you’ve completed the therapy you should continue to have that tolerance. But there are no well-controlled studies that show that. So that means if your child has the therapy, and then three months later stops being fed peanuts, and then they eat them again, they could have a life-threatening reaction.

The second thing is that we don’t yet have good standards, such as how much and how often.  It’s all over the map if you look at studies.  And so, that’s something the FDA is really being shrewd about exploring before they will approve any kind.  The third reason is safety. A number of these studies have significant fallout. Many times people don’t finish the study, often because they have some uncomfortable reactions.  The most common one is an upset stomach.

The uncertainty is the issue here--uncertainty in terms of the objectives you want to achieve and it being long-term enough.  Also, the uncertainty of how much you should give and how often and the uncertainty of safety.  And when we are talking about peanuts, we’re talking about possible fatality.  So, you don’t want even one child to die from this process.

What is the difference between oral immunotherapy and sublingual immunotherapy?

Oral immunotherapy and sublingual immunotherapy are different. Sublingual immunotherapy is where people get a smaller dose of an extract of an allergen, that’s placed under the tongue and is held under there for a couple minutes and then swallowed. What they have in common is you deal with very small amounts that you gradually increase over time.  But with oral immunotherapy, there is more risk than with sublingual, and neither one has been shown to have long-term tolerance yet, when it comes to foods.

What are your thoughts on this study?

It’s very encouraging, but it’s not ready for primetime yet. It’s going to take a lot more research and larger group studies to be able to determine if it is safe enough,  how it should be done, and what happens to these kids three and six months after the study. That’s the big question.

What board-certified allergists, and what I’m recommending every day to my patients, is that it’s still an area of research that is ongoing and needs to be monitored further. Our practice likes to abide by FDA-approved processes and drugs. And, I share with them the concerns about safety, because we’re talking about a challenge with something that could cause throat closure and death.  Even though somebody down the street might be doing it, patients must realize that safety parameters have not been fully established.

What is your advice for people or parents of children with peanut allergies?

There are two major things. People with peanut allergy should have access to some form of epinephrine, and they should have strict avoidance and be aware of how to read labels, because hidden peanut allergens may be in various things that they ingest.