Future Outlook on Food Allergy Treatment
As many families who are affected by food allergies know, the current recommended treatment option for these patients include strict avoidance of the food and carrying epinephrine at all times in case of any accidental exposure. Having a food allergy can be a terrifying diagnosis and studies have even shown that kids with food allergies may suffer from bullying and ridicule at school as a result. It is then comforting for patients and families to know that more treatment options are on the horizon. While these new options have not yet been perfected and do not guarantee that the food allergy will disappear once treatment is completed, there is hope that one day patients will not have to live in fear of their diagnosis.
How food allergies are diagnosed
All food allergy diagnoses first begin with a detailed clinical history and physical exam performed by your allergist. Skin testing and blood testing will then be performed if indicated. If unremarkable, a food oral challenge may be performed. Food oral challenges work by introducing increasing doses of the food in question to the patient at a time. The food in question should be prepared as plainly as possible to avoid adding any external factors when monitoring for an allergic reaction. The patient will wait in between doses and, if no reaction occurs, they can proceed to a higher dose until a complete serving is achieved. If no reaction is observed by your allergist, they will instruct you to monitor for any delayed reactions for the next 24 hours. If none occur, then the patient is said to pass the oral food challenge and they may reintroduce that food back into their diet.
Patients with a strong clinical history for food allergy will most likely have a positive result on skin testing. As skin testing is very sensitive, a negative test is most likely a definitive result whereas a positive result should be further explored. Blood testing may then be ordered, and if the allergy antibody level, IgE, is elevated enough for the food in question, then a food allergy is likely. In this case, oral challenge should not be performed as the patient is most likely allergic to the food in question. The clinical history is highly relevant and is taken into account while making a diagnosis. The hallmark of food allergy includes the development of immediate itchiness, rash, and hives following consumption of the food.
Oral immunotherapy poses as a potential long term solution for wheat, egg, peanut, tree nut, and milk allergy patients. At the end of treatment, over 75% of patients are said to tolerate the food they were once allergic to with no problem. Adverse reactions such as itchiness in the mouth and abdominal pain are common, however most reactions are fairly mild. Severe reactions, although less common, have been found to occur unpredictably in a small percentage of participants who have previously tolerated the dose. At the first visit for treatment, the patient will undergo an initial dose escalation where they begin with a small dose of the food in question and then rapidly increase the dosage. The goal of this initial dose increase is to begin and maintain at subthreshold levels so that a safe starting dose for home administration can be determined.
The patient will then return every two weeks for dose increases followed by observation before they are discharged. Between every visit, the patient is required to take one dose of the desensitization daily at home. Once the treatment is complete, the patient must continue to consume the food every day so as to maintain desensitization. The main controversy over oral immunotherapy is whether patients will become desensitized vs. develop immune tolerance. If the patient is merely desensitized, then they will regain sensitivity if they discontinue consuming the food for a period of time following oral immunotherapy. This means that they are then at risk for developing reactions following consumption of the food if they attempt to try eating it again. If the patient is immune tolerant, they can discontinue consuming the food for a period of time after oral immunotherapy and have no problem upon reintroducing the food into their diet. The challenge of oral immunotherapy is there is no way to predict if a patient will become merely desensitized or immune tolerant.
Sublingual therapy for food allergies has been used predominantly for people with allergies to milk, peanuts, tree nuts, and fresh fruits. Sublingual therapy involves administering small drops of allergen extract under the tongue for approximately two minutes until it is then swallowed. Preliminary data suggests that sublingual therapy is not as effective as oral immunotherapy in inducing desensitization, however it is a safer treatment option as less of the allergen is being introduced at a time. Goals of sublingual immunotherapy vary on a case by case basis, with tolerance being a goal for some patients while others merely hope to reduce the intensity of a reaction in the case of accidental exposure. More studies still need to be performed in order to realize the clinical benefit of sublingual immunotherapy in treating food allergies.
Epicutaneous immunotherapy works to desensitize patients to food allergens through introducing biologically active compounds in small quantities to the outer layer of the skin. This method offers a potentially strong safety profile as it works through the epidermis. Once the patch is applied, it created a condensation chamber which hydrates the skin and solubilizes the allergen which allows it to penetrate the epidermis. This therapy then bypasses the blood stream as it interacts with Langerhans cells, which are located in the epidermis. These cells capture the antigen and migrate to the lymph nodes in order to activate the immune system. This therapy is currently being researched for treatment of both milk and peanut allergies. Treatment would require daily application of the patch to the back or upper arm. This therapy is still being researched and hopefully more information on the validity of the treatment will be available in upcoming years.
Modified Allergen Immunotherapy
Novel therapy ideas are abundant and still in the research settings. One idea involved modifying the protein to be used in immunotherapy by altering its binding site so that it can no longer bind to IgE, which activates the pathway for allergic reaction, although T cell binding would be left uninterrupted. This potential therapy offers not only the chance for a much safer immunotherapy treatment but the ability to escalate dosing much more rapidly. Two methods are currently being investigated, one which limits the reactivity of IgE through modification of the binding sites while the other aims to identify specific binding sites with promote tolerance and using them in peptide immunotherapy. Peptide immunotherapy is currently in phase III trials for cat allergen and in preclinical trials for treatment with food allergens. IgE modification has also been tested in regards to peanut. In trials with mice, the modified allergen did not bind to IgE and there were reduced allergic symptoms when rechallenged. While this trial was successful, phase I trials are still underway as the occurrence of acute allergic reactions have been common, suggesting that IgE binding has not yet been adequately reduced.
As safety is one of the main priorities throughout immunotherapy, treatment methods must be thoroughly investigated prior to any clinical use. With the abundance of novel treatment investigations, there is a high probability that new treatment methods for food allergy patients will be available for use within the next few years. These new treatment options should promote hope to families and patients affected by food allergies and will hopefully make a positive impact on their lives in the years to come. For more information on these new treatment methods, please follow the link below: