Eating nut protein can help treat nut allergies

Most preschoolers who are allergic to peanuts can be safely and effectively desensitized by eating small amounts of peanut protein as directed by allergy specialists, a study led by University of B.C. and B.C. Children’s Hospital researchers shows.

In the study, published Tuesday in the Journal of Allergy and Clinical Immunology: In Practice, 243 children (90 per cent) reached the desired, desensitization dosage in an average period of 22 weeks. The other 10 per cent dropped out for reasons such as repeated allergic reactions and child and parental anxiety. Participants lived in B.C., Alberta, Manitoba and Nova Scotia.

“According to our data, preschoolers with peanut allergies can be considered for oral immunotherapy,” said the lead author, Dr. Edmond Chan, who is the head of pediatric allergy and immunology at UBC and at B.C. Children’s Hospital. “However, it’s important to note that it should always be done under allergist supervision, and not attempted by parents on their own or with health care providers who aren’t allergists.”

He said children with a history of severe, life-threatening reactions to peanuts and those anxious about the treatment are not good candidates for the desensitization approach.

While some experts believe allergic reaction effects can compound and get worse each time anaphylaxis occurs, Chan said the severity of food allergic reactions is difficult to predict. “The likelihood of outgrowing a food allergy depends on the type of food and other factors (and only) about 20 per cent of children outgrow peanut allergy.”

Oral immunotherapy is a new approach in which children consume small amounts of an allergy-causing food with the amount gradually increasing to a predetermined maximum or maintenance level that is held for a year or two. The goal is to desensitize them so that if they are accidentally exposed to the allergen, they won’t have a life-threatening reaction.

In the study, children with a median age of 23 months went to an allergy clinic every few weeks — a total of eight to 11 times — to be watched each time their peanut protein dose was increased. The top daily dose was 300 mg of peanut protein, the equivalent of one peanut or 1 /4 to 1/3 of a teaspoon of peanut butter.

Children in the study ate their doses of peanuts in powder form (mixed into yogurt, for example) or in popular Israeli peanut snacks called Bamba.

Nearly 68 per cent of preschoolers experienced at least one allergic reaction during the buildup phase, but the reactions were largely mild.

Only four per cent of the children in the trial required epinephrine to counteract allergic responses, while 1.5 per cent experienced severe reactions requiring a trip to the hospital emergency department.

Chan said the study should help calm fears about such an approach.

“The goal of our group was to be as safe as possible since this was not a clinical trial and allergists were not always available if an allergic reaction occurred at home.

“So we erred on the side of caution and encouraged parents to give epinephrine if there was a possibility that anaphylaxis was occurring.”

Ravinder Dhaliwal entered her then four-year-old daughter, Saiya, in the study because, as a pediatric emergency nurse at Surrey Memorial Hospital, she has seen how serious peanut and other food allergies can be.

“I’ve seen a lot of anaphylaxis, never a death, thank God, but it’s my biggest fear. At work just recently, a child in anaphylaxis had to be put in the intensive care unit and was then transferred to B.C. Children’s Hospital,” she said.

While her daughter’s allergic reactions in the past were mild, there is no way to predict when a life-threatening response might happen. Her daughter, now five, had only one bout of vomiting after the peanut dose was increased.

It’s about a year and a half since Saiya entered the study, and she can now eat the equivalent of 10 peanuts without a reaction.