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Updated January 26, 2015.

The idea of treating and potentially curing food allergies has been on the minds of researchers for years. Oral immunotherapy (OIT) for food allergies is one avenue of treatment that is under investigation. In the face of growing rates of food allergies among American children under age 18, the hunt for a cure goes on.

With the prevalence of food allergy up by 18%, it’s no wonder scientists look for ways to safely treat them and build tolerance to food allergens.


The prevalence of peanut allergy alone has tripled (0.4% to 1.4%) from 1997 to 2008 (almost a decade). Accidental ingestion of a food allergen, especially due to cross-contamination, is an area of real concern for many with food allergy.

For adults and children, the most frequently caused anaphylaxis is from peanut, tree nuts and shellfish. In children alone, milk and egg reactions are also common. While many (85%) children will eventually outgrow or develop a tolerance for their food allergy to cow’s milk, egg, wheat and other cereal grains, and soy, only a small percentage (15-20%) of children will outgrow peanut, tree nuts, fish and shellfish. Hence, most OIT research is directed at these foods.

"The goal of food oral immunotherapy is to increase the amount of the food antigen, the protein in the food, needed to trigger allergic symptoms in individuals with immunoglobulin E (IgE) mediated food allergy. The ultimate goal is for long-term immunologic changes that would allow the ingestion on the food without symptoms and without ongoing therapy," says Lynn Christie, MS, RD, LD, research project manager dietitian at Arkansas Children’s Hospital who has specialized in the area of food allergies for 15 years.

 

How it’s done

“A food that someone is allergic to is given to them daily and systematically increased to a set amount of protein. This amount of protein ingested on a daily basis may potentially protect the individual from an accidental allergic reaction,” states Christie. During OIT, the allergen food (such as milk, egg or nuts) is mixed with a safe food and eaten in gradually increasing doses. This is first done in a controlled setting like a research center. Once done under observation and without a reaction, the patient goes home on this dose, eating it daily for a prescribed amount of time. Increases in doses are performed at the research center and sustained at home. Doses are increased steadily until the maintenance phase is achieved. The maintenance phase is variable, depending on the study, and food challenges are performed at the end to evaluate tolerance.

Wendy, whose almost 8 year-old daughter has been part of a study for 4 months says, "The worst part has been getting her to actually eat her daily dose."   

Early studies suggested that a subset of food allergic subjects could be “desensitized’ to a variety of foods, including milk, egg, fish, fruit, peanut, and celery. However, some subjects who did well with maintenance doses, even for a long period of time, re-developed allergic symptoms if the food was not eaten on a regular basis.

Studies suggest an ongoing need for allergen exposure, continuing to include it in his diet so that allergen tolerance is sustained, or ongoing.  

It has been suggested that people with transient forms of food allergy (the allergens kids are most likely to outgrow) tend to have the most success with oral immunotherapy to relieve the allergy. Patients with the persistent form of food allergy (peanuts, tree nuts, fish and shellfish) are less likely to have a favorable response to therapy, due to reasons such as inability to desensitize to the food allergen, failure to develop an ability to eat the food, need for a longer treatment course, and the development of more serious negative reactions to the food allergen while on therapy. However, this needs further investigation.

The Future

At the time of this writing, oral immunotherapy is a research-based treatment and is not approved for clinical use. There are no accepted therapies proven to accelerate the development of oral tolerance or to provide effective protection from unintentional exposures to food allergens, but scientists are steadily working toward this.

Early clinical trials have demonstrated that OIT is safe and that it is effective in 70-80 percent of patients, provided that it is properly administered in a controlled setting. However, researchers must determine the most effective dosage and time frame for treatment. Further, they must learn whether or not OIT can desensitize large numbers of patients, and finally, if it can lead to lasting tolerance.

“This is not for everyone,” states Christie. “A small number of people do not tolerate the daily {allergen} doses, and individuals who participate in research are closely monitored.” This means appointments, getting off of work and travel for some families. “Some families don’t want their child to have an allergic reaction (all studies have food challenges to help evaluate effectiveness of treatment,) or may fear the unknown,” says Christie.

Some newer studies combine OIT with an asthma medication, in an effort to help minimize the frequency of reactions to OIT. If proven successful, this combined regimen would allow physicians to safely escalate patients’ intake of food allergens, resulting in more rapid desensitization than OIT alone. 

Resources:

Nowak-Wegrzyn A and Sampson H. Future Therapies for Food Allergies. J Allergy Clin Immunol. March 2011; 127 (3): 558-573.

Sicherer SH. Food Allergies: A Complete Guide for Eating When Your Life Depends on It. 2013. The Johns Hopkins University Press. Baltimore, MD.