Oral allergy immunotherapy involves giving the allergen by mouth. It comprises the daily consumption of milligrams to grams of allergen, typically mixed with a food vehicle, which is incrementally increased over weeks to months with the goal of inducing desensitization and ultimately tolerance.
Open-label pilot studies involving patients with milk, egg, and peanut allergies had suggested that oral allergy immunotherapy could increase the threshold of clinical reactivity to the culprit food. Recent RCT have provided further compelling evidence that oral allergy immunotherapy can frequently induce desensitization in patients with food allergy, although the effect varies across studies.
There is evidence that oral allergy immunotherapy can also result in clinical tolerance or sustained unresponsiveness. In 2012, Keet et al. reported that 40% of subjects receiving milk oral allergy immunotherapy passed an OFC when treatment was ceased for 6 weeks, although it is possible that some may have naturally outgrown their food allergy. That same year, a study by the Consortium for Food Allergy Research (CoFAR) found that of 30 patients desensitized with egg oral allergy immunotherapy, eleven (27.5% of the active treatment group) passed on OFC after halting therapy for 4–6 weeks. These individuals continued to consume egg regularly without problems when surveyed 12 months later. The likelihood of spontaneous food allergy resolution was very low in this study, and none of the control subjects exhibited evidence of outgrowing their egg sensitivity. This landmark article was the first to suggest that oral allergy immunotherapy could be a truly disease-modifying treatment.
More studies are needed for the testing of oral allergy immunotherapy in the treatment of food allergy.
Moran TP et al. Oral and sublingual immunotherapy for food allergy: current progress and future directions. Current opinion in immunology. 2013;25(6):781-787. doi:10.1016/j.coi.2013.07.011.