01/29/2014 18:31 EST | Updated 03/31/2014 05:59 EDT

Peanut allergy in children reduced in experiment

Some children with peanut allergies who were given small doses of peanut product were able to build up their tolerance and improve their quality of life after participating in a carefully controlled experiment.  

British researchers followed 96 children and teens with varying degrees of documented peanut allergy. After six month of treatment with increasing doses of peanut protein, most of the participants could safely tolerate the equivalent of about five peanuts — a reassuring change for families worried about accidental exposures.

"This study shows that peanut immunotherapy is an effective and well-tolerated treatment in this age group" of seven to 16 year olds, study leader Dr. Andrew Clark from Cambridge University Hospitals and his co-authors conclude in Wednesday’s online issue of the medical journal The Lancet.

In the British study, one patient had to administer epinephrine twice for symptoms and dropped out. About 20 per cent had reactions involving wheezing that was mild in most cases and responded to a standard puffer. Others complained about itchy mouth and abdominal pain, which also weren’t severe enough to require hospital care.

Peanut allergy is the most common cause of severe and life-threatening allergic reactions related to food, affecting between 0.5 per cent and 1.4 per cent of children in high-income countries, according to the journal.

Dr. Susan Waserman, an allergist and immunologist at McMaster University in Hamilton, is conducting a similar clinical trial of 32 children aged five to 10 who are taking protein powder or a placebo in jam or pudding.

Waserman said the British findings cast the approach in a good light.

"In a disease where we teach everybody that even a trace amount of peanut can be fatal, this is actually quite good news, and pretty revolutionary," Waserman said.

Being able to tolerate 800 milligrams of peanut protein or about five peanuts is going to "increase their quality of life and just make them less anxious about having this whole condition," Waserman said.

So far, some of Waserman’s own participants have had similar success, and other trials are under way in other countries.

The approach isn’t ready for use by families and their doctors, Waserman cautioned. It’s also not a cure that allows people to enjoy peanut butter sandwiches freely. Rather, researchers still need to determine the minimum amount of peanut needed to maintain the tolerance. Otherwise, the allergy sensitivity seems to creep back.

A larger and broader range of people need to be followed for longer to see if "oral immunotherapy" remains safe and is cost-effective, Matthew Greenhawt from the University of Michigan Food Allergy Centre in Ann Arbor said in a journal commentary published with the study.

It would be naive to view oral immunotherapy as a one-size-fits-all treatment for food allergy, Greenhawt said.

The study was funded by the Medical Research Council.