Study: For Peanut Allergies, Peanut Therapy

Some people just need to be eased into it.

Dan Riedlhuber/Reuters

PROBLEM: There's no known treatment for peanut allergies. Which sucks, because they're the most common trigger of severe and fatal anaphylactic (or, as spell check prefers I call them, "anticlimactic") reactions, and sufferers need to be forever on their guard to avoid accidental contact with a peanut. But hey, since everything else has failed, why not go ahead and try putting them in contact with a peanut?

METHODOLOGY: With the support of the National Institutes of Health, 40 subjects with peanut allergies were gathered at five different hospitals for a trial of "sublingual immunotherapy," or the placing of peanuts under their tongues. Specifically, half received a placebo, while half received a really, really tiny amount of peanut protein (they started out with a 1:20,000,000 weight/volume dilution).

Before and after the treatment, during which the peanut dose was increased incrementally, the participants were subjected to a "food challenge" during which researchers measured how much peanut powder they were able to eat without having an allergic reaction. Winning the food challenge, first time around, involved having an allergic reaction after ingesting less than 2 grams of peanut powder, making them allergic enough to qualify for the study. Winning, after treatment, meant being able to tolerate 5 grams or more.

RESULTS: Of the 20 participants given peanut therapy, 14 were able to eat ten times more peanut powder after 44 weeks of daily treatment (two had withdrawn by this point). After 68 weeks, three "won" -- they were able to consume 5 grams -- and two made it all the way to 10 grams, making them peanut powder champions. The under-the-tongue doses mostly only caused minor side effects, like itchy mouth, which does count as anaphylaxis, but only "grade 1" -- respiratory arrest doesn't occur until "grade 5."

Interestingly, three of the 20 placebo participants also increased their peanut powder tolerance after 44 weeks, and two even passed the challenge, illustrating the other, simpler "cure" for peanut allergies: "Spontaneous tolerance development."

CONCLUSION: Peanut therapy is "relatively safe" and has potential to, if not cure peanut allergies, at least desensitize patients to the point where accidental ingestions of small amounts won't cause serious harm.

IMPLICATIONS: Since they were erred on the safe side and didn't accept subjects with deadly allergies, researchers still aren't sure if such patients can safely sustain peanut treatment. If peanut therapy is eventually put into practice, though, it's assumed that these will be the people most likely to seek it out.

And, as with any of our Studies of the Day, don't try this without proper medical supervision.

The full study, "Sublingual immunotherapy for peanut allergy: A randomized, double-blind, placebo-controlled multicenter trial," is published in the Journal of Allergy and Clinical Immunology .