Food Allergies can be tested and treated with oral food challenges or food desensitization.
What is the difference between an Office Food Challenge (OFC) and Oral Immunotherapy (OIT) ?
An OFFICE FOOD CHALLENGE (OFC) is used as a medical test when the food allergy is in question, and will either confirm or rule out the presence of the allergy. ORAL IMMUNOTHERAPY (OIT) is a medically supervised therapy in which the patient eats small, gradually increasing amounts of a food on a daily basis to which they are known to be allergic, with the goal that over time the patient will become desensitized or tolerant to it.
Oral Food Challenge
What is a food challenge?
An oral food challenge (OFC), or feeding test, is a medical procedure in which a food is eaten slowly, in gradually increasing amounts, under medical supervision, to accurately diagnose or rule out a true food allergy.
What are the reasons to perform an OFC?
OFCs are usually done when a careful medical history and allergy tests, such as skin and blood tests, are inconclusive. The OFC is a more definitive test because it will show whether the food ingested produces no symptoms or triggers a reaction.
What do I need to do in preparation to have an OFC?
You need to be in good health on the day of the test. Chronic allergic conditions such as asthma, atopic dermatitis (eczema) and allergic rhinitis (hay fever) have to be well controlled so they do not interfere with the interpretation of any symptoms. If you are sick on the day of the test, postpone it. You should also carry your usual medications and emergency medications with you so you have them for the trip to the doctor and back.
Do I have to stop any medications before having an OFC?
Yes. Antihistamines have to be stopped before the OFC since they might mask mild early symptoms. Ask your doctor how long you need to be off the type of antihistamine you are using. It may be difficult to stop allergy medications during an allergy season or in patients with significant eczema, therefore OFCs may need to be timed to avoid the seasons that cause problems.
Who provides the food?
Talk to your doctor. Some may have you bring specific items, others may provide the food. Discuss your child’s food preferences. For infants, younger children or picky eaters, you may need to have several food options ready to minimize the possibility of food refusal for a picky eater. For example, soy may be tested as edamame, tofu, soy ice cream or soy milk.
For children, bring favorite serving dishes and utensils, and distractions such as toys, books, or homework.
What happens on the day of the test?
You may be instructed to avoid food or have a very light meal before starting. A physical examination and vital signs are done before starting and periodically during the test. The OFC starts with a small serving of the food and after a period of time, usually 15-30 minutes, if no symptoms are present, a slightly larger amount is eaten.
Before each subsequent dose, careful evaluation is performed to look for any symptoms. If symptoms occur, and the medical personnel judge that a reaction is happening, the feeding is stopped and medications are given as needed. Otherwise, the feeding continues until, typically, a meal sized portion is eaten.
What is the usual treatment in case of an allergic reaction during an OFC?
Most food challenges that result in a reaction trigger skin or stomach symptoms. The symptoms are usually mild because the testing is done gradually with small amounts of food at the start, and feeding is stopped at the onset of symptoms. Most often, antihistamines are given for these mild symptoms. If there are more severe symptoms, treatments can include epinephrine and other medications.
How long do I have to stay after the feeding is over?
If there were no symptoms during an OFC, usually patients are discharged from the office within 1to 3 hours of completing the feeding. In case of allergic symptoms, the patient is typically watched for at least 2 to 4 hours from the time symptoms go away or improve, with longer observation periods required for patients with more severe reactions.
Are OFCs different for different forms of food allergy?
Most food allergies lead to symptoms soon after the food is ingested. However, some forms of food allergy are delayed. For example, in food protein-induced enterocolitis (FPIES), symptoms typically do not begin for at least 2 hours and so the feeding is performed faster and the observation time is longer than for typical allergies. The dosing and observation time for an OFC can be adjusted to address an individual patient’s pattern of reaction.
What are the post-test instructions?
If the OFC did not cause symptoms, the patient is recommended to start regular consumption of the challenge food at home the following day. It is usually advised to make the food a routine part of the diet. Having symptoms after a “passed” OFC is uncommon.
If the OFC resulted in an allergic reaction, then continued avoidance is recommended.
What are the OFC risks?
The risks of OFC include an allergic reaction including anaphylaxis. There is no evidence that having an allergic reaction during an OFC makes future reactions worse or prolongs allergy in children.
What is oral immunotherapy for food allergy?
Oral immunotherapy (OIT) refers to feeding an allergic individual an increasing amount of an allergen with the goal of increasing the threshold that triggers a reaction. For example, a person allergic to peanuts may be given very small amounts of peanut protein that would not trigger a reaction. This small amount is gradually increased in the allergist’s office or a clinical research setting over a period of months. The goal of therapy is to raise the threshold that may trigger a reaction and provide the allergic individual protection against accidental ingestion of the allergen. OIT is not a curative therapy. Individuals who receive OIT will continue to carry epinephrine, read labels closely, etc., and it is not expected that OIT will lead to ingestion of the allergen without limitation.
What is the current standard of care for treatment of food allergy?
The current standard of care for treatment of food allergy is avoidance of the allergen and treatment of anaphylaxis with auto-injectable epinephrine. While many food allergy treatments, including OIT and epicutaneous immunotherapy (EPIT, or a skin patch), have been considered investigational by professional allergy societies and other key stakeholders, the Allergenic Products Advisory Committee of the Food and Drug Administration (FDA) recently voted to support approval of a standardized oral immunotherapy (OIT) product for peanut allergy. Previously known as AR101, the brand name is expected to be PalforziaTM. The proposed indication is for treatment to reduce the incidence and severity of allergic reactions, including anaphylaxis, after accidental exposure to peanut in patients aged 4 to 17 years with a confirmed diagnosis of peanut allergy. The FDA now requires submission of a Risk Evaluation and Mitigation Strategy for review and approval.
What is the current standard of care for treatment of food allergy?
The current standard of care for treatment of food allergy is avoidance of the allergen and treatment of anaphylaxis with auto-injectable epinephrine. While many food allergy treatments, including OIT and epicutaneous immunotherapy (EPIT, or a skin patch), have been considered investigational by professional allergy societies and other key stakeholders, the U.S. Food and Drug Administration (FDA) on January 31, 2020 approved PALFORZIA™ [Peanut (Arachis hypogaea) Allergen Powder-dnfp], a standardized oral immunotherapy (OIT) product for peanut allergy. It is indicated for the mitigation of allergic reactions, including anaphylaxis, that may occur with accidental exposure to peanut in patients aged 4 to 17 years with a confirmed diagnosis of peanut allergy. The FDA requires that PALFORZIA is available only through a Risk Evaluation and Mitigation Strategy (REMS). PALFORZIA is to be used in conjunction with a peanut-avoidant diet and is contraindicated in those patients with uncontrolled asthma and eosinophilic esophagitis and other eosinophilic gastrointestinal disease.
How effective is OIT?
Efficacy in clinical trials has typically been defined by induction of a desensitized state. “Desensitization” refers to the improvement in food challenge outcomes after therapy and relies on ongoing exposure to the allergen. Peanut, egg and milk OIT have been shown to desensitize approximately 60 to 80% of patients studied. Desensitization rates for other foods have not been as closely studied and some evidence suggests OIT may not be equally efficacious for every food allergy. It is important to note that because efficacy has been measured using oral food challenges in trials, it is not yet definitively known whether desensitization can protect patients from real-world accidental exposures (e.g. prevent hospitalization or death).
Some studies have looked at “sustained unresponsiveness” which refers to retention of the protective benefit achieved through therapy and is not reliant on ongoing exposure. Sustained unresponsiveness has not been adequately studied to provide definitive data. Peanut and milk OIT have been reported to induce sustained unresponsiveness in approximately 30 to 70+% of individuals, though a number of variables make broad interpretation of this data difficult, including age of participants in the studies, length of time on therapy, and length of time off therapy at the time the sustained unresponsiveness was assessed. It is assumed that ongoing exposure will be required for the majority of individuals receiving OIT or EPIT; the therapies in their current form are unlikely to produce a permanent, long-standing immunologic change.
What are the side effects of OIT?
The most common side effects involve the gastrointestinal (GI) tract. Typical symptoms include abdominal pain, vomiting and cramping. Some patients have developed eosinophilic esophagitis (EoE), an allergic disease of the esophagus that causes difficulty swallowing, vomiting and abdominal pain, but it is not always clear that EoE was caused by the therapy. EoE typically resolves when therapy is discontinued. Other commonly reported side effects include oral itching, rash, hives, swelling, wheezing and anaphylaxis.
What are some “real-life” considerations with OIT?
Studies thus far have brought to light several “real-life” considerations that will be important to understand as treatment with OIT becomes available. OIT involves a long-term commitment with daily dosing during the up-dosing and maintenance phases which occur over several months to years and possibly indefinitely. Bi-weekly office visits are required to safely assess the tolerability of each consecutive dose level. When dosing at home, certain precautions increase safety but also place restrictions on daily life, such as a home monitoring period after dosing and avoiding an elevation in body temperature (e.g. with exercise, hot showers, etc.) for 2to 4 hours after dosing. In addition, aversion to the taste and smell of the product can be tough to overcome for those who have practiced lifelong avoidance.
What is unknown about OIT?
There are many important questions about OIT that require ongoing study. The precise degree of protection is a topic of active investigation. Will OIT allow individuals to reliably eat products with precautionary labels? The length of treatment and doses used have varied in published studies. The “best” dose to give for any particular allergen is unknown. How to predict which individuals would respond to treatment and those at highest risk of side effects is also unknown. Do treatments have long-term safety risks different from those observed in clinical trials? Is there a way to measure benefit without performing an oral food challenge? Is long-term treatment sustainable? What are the effects of long-term treatment on quality of life and family dynamics? What are the effects of suboptimal adherence on safety and efficacy? Could OIT be combined with another therapy to improve safety and efficacy?
What OIT has been approved for the treatment of food allergy?
The only FDA approved treatment for food allergy is the aforementioned peanut OIT product, PALFORZIA™. Other programs for egg and walnut allergies have been announced. There are also a relatively small number of allergists around the country who use commercial food products to offer OIT as a service in their offices, a clinical practice which is not currently and will not be “approved” by the FDA. Only REMS certified providers will be able to prescribe PALFORZIA™.
What else should individuals affected by food allergy and their families be aware of when considering OIT?
OIT is a leading investigational and now, marketed treatment, offering the hope of protection from food allergy reactions. However, like most chronic diseases, food allergy treatment will not be a “one size fits all” approach. Thus far, OIT has primarily targeted allergy to single foods; further study is required to determine if multiallergen OIT will be beneficial. Other investigational therapies may become available and carry different risks and benefits. In addition to the safety profile, important considerations will include likelihood of outgrowing an allergy naturally, prevalence of food in the diet/culture, severity of allergy, and risk of exposure. Ultimately, the choice of treatment, including that of active non-intervention, will be based on individual and family factors after careful discussion with one’s physician.