A program in Montreal is having good success helping kids with milk allergies build up a tolerance to the drink, one drop at a time.

The McGill University Health Centre’s Allergy and Immunology Lab offers one of the only oral desensitization programs in Canada. The treatment they offer -- also called immunotherapy -- involves giving patients with food allergies small, incremental doses of the allergenic food in hopes the body learns to tolerate the food allergen instead of react to it.

Dr. Bruce Mazer, a pediatrician and allergy specialist at MUHC, says the program introduces the allergen very slowly, over a two-day period, beginning with minute amounts, such as 0.101 ml of milk diluted several times.

“And then slowly, over the first two days, we get them to be up to a half of teaspoon of milk,” Mazer says.

The doses continue to increase until doctors can give kids 300 millilitres of milk – more than one cup. Mazer says the immune system eventually learns not to overreact to milk.

“The cells that make the antibodies and the cells that coordinate the antibodies, they start learning that milk isn't so bad and they start building up cells that say, ‘Okay let's calm down the immune system’,” he explained.

Sometimes, the therapy doesn’t work and the body overreacts. The doctors then have to go back to the previous dose that had been well tolerated and try again.

The therapy has to be done under strict medical supervision, because the allergic reactions can be severe and maybe even fatal. It doesn't always work for everyone, but MUHC says that since their program started two years ago, 15 kids from around Quebec have become allergy-free.

One of the patients in the program is 13-year-old Lea Tremblay-Benoit. She has been allergic to milk since she was a baby and says her allergy has made life difficult.

“You can't really eat what you want because it contains milk or traces of milk,” she says.

Her father, Jean-Francois Benoit, says Lea’s allergy means they can’t take her to restaurants. Travelling is difficult too, because so much meal planning is required.

The MUHC program has given Lea hope that, one day, she can try ice cream from Laiterie de Coaticook, a nearby dairy.

The MUHC doctors say, if their milk allergy program goes well, they hope to expand it to eventually other allergenic foods, including eggs and nuts.

With a report from CTV Montreal’s Tania Krywiak