Contrary to what you might think, the most common food allergen for young children isn't peanuts — it's the protein in cow's milk.
Reactions vary, but can be severe: hives, vomiting, and sometimes life-threatening anaphylactic shock. Milk, and its derivatives, lurk in some unexpected places, too, including canned tuna fish and even McDonald's fries.
The most common treatment for allergic children is to completely eliminate cow's milk from a child's diet. But sometimes doctors try desensitization — incrementally introducing more and more milk to the kid's system until the allergy fades. Now, researchers are looking for ways to speed up the process.
"Your body can slowly get used to the allergen," Dr. Dale Umetsu, a professor of pediatrics at Harvard Medical School, tells Shots. "But with this process you still have a fairly significant amount of allergic reactions. One has to go very slowly."
Now, after a very small pilot study, Umetsu and his colleagues think they might be on the trail of a way to accelerate desentization. They gave allergic kids milk after an injection of an asthma drug called Xolair, known generically as omalizumab.
With Dr. Linda Schneider of Children's Hospital Boston and Kari Nadeau of Stanford's Lucille Packard Children's Hospital, Umetsu studied 11 kids (average age, 8) who had history of significant symptoms. After an initial dose of Xolair, they gave the kids 0.1 milligrams of milk — a tiny fraction of a drop. Over the course of 10 weeks, they worked their way up to a quarter cup.
"Previous studies trying to do similar things [without the drug] would take four months to two years," Umetsu says.
Xolair, sold by Genentech, is normally used to treat asthma triggered by allergies. It binds to immunoglobulin-E (IgE) — antibodies that normally attach to allergens and then signal cells of the immune system to start the allergic response. Xolair blocks IgE from going into action, and that gives the kids a chance to build up resistance.
Like all medications, Xolair has side effects, which include some swelling at the injection site and cold symptoms. In rare cases, it actually causes anaphylactic shock. And it's pricey. A single shot cost about $300 to $500, which would add up to about $6,000 over the course of the treatment that was tested.
The purpose of this small clinical trial was just to assess the safety of Xolair, but the results suggest it might help kids more quickly build resistance to dairy proteins. Larger studies would be needed to prove that and to provide evidence to the Food and Drug Administration for approval of the drug for that use.
Still, at the end of the study, after researchers stopped administering the drug, 9 of the 11 children were able to drink about a cup of milk a day. "We still saw allergic reactions, but we believe we can figure out ways to reduce those reactions even further," Umetsu says. "Adjusting the dose, and the period of treatment, we can perfect this approach."
The study was funded in part by the Bunning Food Allergy Project and Genentech, as well as Stanford, Harvard, and numerous allergy organizations. The results were published this week in the Journal of Allergy and Clinical Immunology.