Can a little exposure to peanuts lessen severe reactions in allergy sufferers?

A doctor gives a child allergic to peanuts pudding that contains peanuts in hopes of desensitizing him against his condition.

Giving peanuts to a child with a severe allergy would normally be unthinkable, but some doctors in Canada are doing just that, in a bid to train the children’s immune systems to better tolerate the food.

Researchers at McMaster University are working on a therapy in which children with peanut allergies are given the tiniest of doses of peanut protein powder in a pudding, in hopes of desensitizing them against the condition.

It's called oral immunotherapy and while the McMaster team hasn'tt yet published their reserach, a recently published U.S. study testing a similar method suggests the approach may work.

Federal researchers with the U.S. National Institutes of Health tested concluded their method helps reduce the allergic response in many of those who try it.

In their Journal of Allergy and Clinical Immunology report, they tested the therapy on 40 people under the age of 37. In half the group, a tiny amount of a peanut powder liquid was placed under their tongues every day; the other half got a placebo. The dose was then increased incrementally.

After 44 weeks, 14 of the 20 participants who were given the actual peanut powder were able to consume at least 10 times more peanut powder than they could at the beginning of the study.

For most, that meant being able to handle five grams or more of peanut powder. Two in the group were able to tolerate 10 grams. (Two others in the treatment group dropped out along the way.)

The therapy caused only minor side effects, such as itching in the mouth, though one participant developed a severe enough reaction during one session that he required a dose of epinephrine.

The researchers noted that their study was a short one and was not able to determine whether the tolerance the subjects developed can be maintained over the long term.

Dr. Susan Waserman, who is leading the research at McMaster, says the therapy could be life-changing for those with peanut allergies.

“I think the demand is potentially huge. It is a very prevalent problem, it is increasing in scope, and up until now we have nothing beyond avoiding the particular food,” she says.

“Will this be something that will be applicable to everybody still remains to be seen. But it is exciting for us because until now, we have had nothing in terms of food allergy treatments.”

The goal of the therapy is not to cure a peanut allergy, but to lessen the severity of an allergic reaction if sufferers accidently consume a small amount of peanut.

And the research comes at a pressing time: the number of people diagnosed with peanut allergies has double over the past 15 years.

Still, researchers caution that those with food allergies should never try to develop tolerance on their own and that this form of oral immunotherapy should be administered only under the guidance of trained clinicians.

Doctors are also testing a peanut patch that would release peanut protein into the skin to desensitize those with the allergy. The hope is that going through the skin will be a safer approach that oral therapy.

“The patch is actually peanuts being presented to the immune system (and it’s) supposed to desensitize patients in a way that hasn’t been used before,” explains Dr. Gordon Sussman, of Toronto’s St. Michael’s Hospital. “So it’s a novel way to allow the immune system to develop a tolerance, and possibly a cure.

“It’s a better way of treating peanut allergies than having people be afraid of peanuts … for their whole lives.”

Doctors expect results from each of several studies early next year.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip