THE QUESTION Might gradual exposure to peanuts make people who cannot tolerate them less likely to have an allergic reaction?
THIS STUDY involved 40 people, 12 to 37 years old, with a peanut allergy diagnosis but no history of life-threatening reactions. Before the study began, their ability to eat peanuts without symptoms was measured. They were then randomly assigned to consume gradually increasing amounts of peanut powder or a placebo, dissolved in a liquid, daily. Participants held the substance under their tongue for two minutes before swallowing it, a method known as sublingual immunotherapy. Doses increased about every two weeks. When tested again after about 10 months, 70 percent of those who were being exposed to peanuts (vs. 15 percent of the others) could consume 10 times the amount that they could consume without symptoms at the start of the study. During the study, participants consuming the peanut substance had allergic symptoms, usually requiring treatment with an oral antihistamine, about 40 percent of the time, compared with 5 percent of the time for the placebo group; one person had a severe reaction but did not require hospitalization.
WHO MAY BE AFFECTED? People allergic to peanuts, one of the most common food allergies and the substance most likely to cause a deadly reaction, known as anaphylaxis. Although some people outgrow their allergy to peanuts, most do not and must be vigilant about food consumption throughout their life to avoid exposure and potentially risky reactions.
CAVEATS No one who is allergic to peanuts should experiment with exposure to the allergen without close medical supervision. The study did not test whether sublingual immunotherapy might be appropriate for people with a severe peanut allergy. The authors noted that sublingual immunotherapy reduced participants’ sensitivity to peanuts but that the results “offer no insight into long-term tolerance or incorporation of the food into the normal diet.”
FIND THIS STUDY January issue of the Journal of Allergy and Clinical Immunology.
The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.