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 months of treatment with increasing doses of peanut protein, about 80 per cent of the children were able to tolerate the equivalent of about five peanuts and two-thirds were able to tolerate up to 10 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.
'May contain' peanut fears
The approach isn’t ready for use by families and their doctors, Waserman cautioned. "This is something that could potentially give quite serious side-effects."
Steve Kalampalikis's son, Michael, is one of the subjects in Waserman's study. He says the treatment has made a huge difference in the eight-year-old's independence.
"We feel safe sending him off to a birthday party without hovering over and making sure he's not grabbing anything that he shouldn't be eating," Kalampalikis said.
Michael recalls accidentally having a peanut before the experiment. "My throat started swelling up. It was really scary." He said he sometimes still feels nervous eating a couple of peanuts, although he's getting more used to the taste.
"Kids in my class always bring in things that 'may contain' and I can have it now."
But it’s 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.
For years, allergists have been using allergy shots for pollen and now under-the-tongue tablets are available. During treatment, an antibody in the body that causes a severe allergy, called IgE, appears to drop, and cells that are responsible for allergic reactions may deactivate, Waserman said. Peanut allergy researchers are measuring all of these to try to understand what's happening.
A larger and broader range of people need to be followed for longer to see if "oral immunotherapy" for peanut allergy 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. Two of the study's authors have a patent application for the study protocol. Greenhawt is a member of an educational advisory council for the U.S. National Peanut Board.