8% of children and 2% of adults have food allergy. More than 170 different foods have been reported to cause allergic reactions.
The mechanisms causing food-induced allergic reactions can be:
- IgE mediated
- non-IgE mediated
- related to cellular mechanisms
- associated with eosinophilic inflammation
- a mixture of multiple mechanisms
Management of food allergy is complicated by varied misconceptions within the medical community and the public at large.
Guidelines development for food allergy
Diagnostic tools have primarily focused on IgE-mediated food allergy with implementation of skin prick and allergen-specific IgE testing to make the correct diagnosis, or rule out IgE-mediated disease, as in the case of food protein–induced enterocolitis syndrome (FPIES).
In 2010, the National Institute of Allergy and Infectious Disease published the first “Guidelines on the diagnosis and management of food allergy”.
In 2012, the International Collaboration in Asthma and Allergy assembled an expert panel and published an international consensus. The European Allergy and Asthma guidelines have been published as a working document. A committee formed by the Joint Council of Allergy and Immunology (JCAI) is preparing an updated food allergy practice parameter. The AAAAI has published a guideline about the performance of oral food challenges (OFCs).
New diagnostic tools for food allergy
Component-resolved diagnostics (CRD) testing has recently been approved by the FDA for peanut allergy. CRD uses allergenic proteins derived from recombinant DNA or purification from natural sources to identify sIgE reactivity to recombinant allergenic proteins rather than whole allergen. The current evidence does not support broad clinical use of CRD testing.
sIgE antibodies to Ara h 2 are the most common peanut allergen associated with clinical reactivity. Presence of Ara h 8 alone in patients with birch pollen allergy (with positive Bet v 1 results) might be the source of cross-reactive proteins that increase whole peanut IgE without clinical relevance. However, inconsistencies exist. Different Ara h peanut components have been implicated (in addition to Ara h 2).
CRD did not improve diagnostic accuracy in predicting egg or milk OFC outcomes.
Dietary avoidance and early introduction of food allergens
Many food allergies take long to "outgrow". Even food allergies that are not classically “lifelong” (eg, milk, egg, and soy) are present well into the school-age years for many patients.
Current guidelines for introduction of foods in infants at high risk for food allergy suggest:
- breast-feeding for 4 to 6 months with delayed solid introduction
- use of a hydrolyzed formula for supplementation
- no dietary restrictions in pregnant or lactating women
- delays in allergenic food introduction for children with known food allergy
There is no evidence to make recommendations about the timing of major food allergen introduction.
Food challenges with heated egg and milk proteins in children with milk and egg allergy is an active research area.
New epinephrine autoinjector device
A new epinephrine autoinjector, Auvi-Q (Sanofi) was approved by the FDA n 2012. It has both audio and visual cues that guides the user through each step of the injection process. This device is available in both 0.15- and 0.3-mg doses (same doses as EpiPen).
New billing code for OFC in the U.S. - International Classification of Diseases–ninth (ICD-9) revision coding
The very modest reimbursement for OFC has been a barrier resulting in underuse of this very effective diagnostic tool. Two new codes to better describe ingestion challenge (IG) were approved in 2012 and go into effect January 1, 2013:
- 95076 describes the baseline ingestion (food) challenge and covers the first 2-hour period of an oral challenge; most IGs, particularly open food challenges, fall under this code
- the more complicated IGs last longer than 2 hours, and for these situations, a second add-on code (95079) has been assigned. This code is billed on an hourly basis for the remaining period of the challenge.
For a food challenge that lasts less than 61 minutes total, under CPT rules for timed codes, the clinician cannot bill the IG code but should only bill for this as an evaluation and management service.
JCAAI, representing allergy, has successfully obtained approval for two new codes for ingestion challenge testing - with a significant increase in reimbursement over 2012. The old code – 95075 - will no longer be recognized - effective January 1, 2013. As of that date, the first two hours of an ingestion challenge will be coded 95076 and each additional hour will be coded 95079. The RVUs for 95076 are 3.45, an 85% increase in reimbursement. The RVUs for each hour of additional challenge time beyond two hours and 31 minutes is 2.41 RVUs. Added together, reimbursement for a three-hour challenge will increase approximately 300% over last year. Source: JCAAI (PDF).
Many organizations have worked to improve awareness and raise funds for research. A list of their websites is provided below:
Labeling laws and food safety
The US Food Allergen Labeling and Consumer Protection Act of 2004 (www.fda.gov/Food/FoodSafety/FoodAllergens) requires labeling of foods related to the “major allergens” (egg, milk, wheat, soy, fish, crustacean shellfish, peanut, and tree nuts). A significant labeling exemption is related to highly refined oils derived from food allergens (e.g. peanut oil).
The US law does not regulate the use of advisory labeling, such as “may contain” or “manufactured on equipment with”.
Commercial airline travel safety
The “Top 10 tips for airline travelers with food allergy” are available at foodallergy.org.
Food Safety Modernization Act and Food Allergy and Anaphylaxis Management Act (2011)
This law requires that the US Secretary of Health and Human Services develop and make available to schools a voluntary policy to manage the risk of food allergy and anaphylaxis among students.
School Access to Emergency Epinephrine Act
A few states have laws related to stock epinephrine. 24% of all epinephrine administrations at school were provided to people whose allergy was unknown at the time of administration. Mylan Specialty pharmaceutical company has enacted a program, “EpiPen4Schools,” beginning in August 2012. This program allows for acquisition of up to 4 free EpiPen or EpiPenJr autoinjectors with a prescription, to schools (www.EpiPen4Schools.com).
The terms desensitization and tolerance are often used:
- Desensitization refers to a change in the threshold dose of ingested allergen required to induce allergic symptoms after food exposure occurring during therapy
- Tolerance refers to the long-lasting effects of treatment that persist after the treatment is stopped and allow a patient to fully consume the food
The development of tolerance remains controversial in food allergy therapeutics. The concept of “sustained unresponsiveness” has been introduced. This area is a subject of ongoing research.
Humanized monoclonal anti-IgE
Omalizumab, a recombinant, humanized, anti-IgE mAb therapy has been used in 2 randomized controlled trials for peanut allergy. The trials did not show significant bnefits. Currently, trials are in progress evaluating anti-IgE both as monotherapy and as an adjunct to oral immunotherapy (OIT).
Chinese herbal therapy
Food allergy herbal formula (FAHF-2) contains 9 herbs and is currently in trials. The herbal formula FAHF-2 contains 9 Chinese herbs and is currently in clinical trials for allergy to peanut, tree nuts, sesame, fish, or shellfish.
Oral immunotherapy (OIT)
OIT is associated with clinical and immunologic responses, but it has limitations because of side effects. GI side effects (pain, cramping, nausea, and vomiting) occur in 10-20% of subjects receiving OIT, requiring discontinuation of therapy.
Viral infections, menses, and exercise may decrease the reaction threshold for subjects receiving stable OIT dosing.
Desensitization was associated with:
- increased allergen-specific IgG4 levels
- decreased skin prick test responses
- decreased basophil activation
- decreased TH2 cytokine (IL-5 and IL-13) production
- increased regulatory T-cell numbers with peanut OIT
Specific IgE levels initially increased and then decreased after the first year of study. These changes are similar to the ones observed with the well-established SCIT for airborne allergens.
Tolerance has not been fully defined, or achieved, in clinical trials.
Extensively heated milk and egg protein
A possible alternative or adjunct treatment to OIT is the use of heated allergen to alter protein conformation and reduce IgE binding. Up to 70% of children with milk or egg allergy can safely consume these extensively heated proteins. This is associated with reductions in TH2-type immune responses and accelerated tolerance development.
SLIT as a treatment for food allergy has been associated with successes for kiwi, hazelnut, peach, milk, and peanut allergies. Side effects were predominantly oropharyngeal. However, the maximal dose administered in SLIT is limited by the small volume, thus OIT is used in most new studies.
Epicutaneous immunotherapy (EPIT)
EPIT was used in one trial in children with milk allergy. Additional studies are in progress for peanut allergy.
Educational materials related to the 8 most common food allergens are available through foodallergy.org and CoFAR cofargroup.org.
Food allergy programs for schools
“How to C.A.R.E. for students with food allergies: what educators should know” is a free, interactive online course available at AllergyReady.com.
A useful food allergy mnemonic is "CARE":
- Comprehend the basic facts about food allergies
- Avoid the allergen
- Recognize the symptoms of a reaction
- Enact an emergency protocol (Epinephrine)
The Food Allergy Management and Education program for schools was developed by St Louis Children’s Hospital. They have developed a toolkit which is available free of charge at www.stlouischildrens.org.
The changing CARE for patients with food allergy. The Journal of Allergy and Clinical Immunology, Volume 131, Issue 1 , Pages 3-11, January 2013.