Beyond inappropriate use of epinephrine, individuals who are at highest risk of death are adolescents and young adults, people with known food allergy and previous history of anaphylaxis, people with asthma (especially if poorly controlled), and people with peanut or tree-nut allergies. 


In addition to these medication recommendations, providers should suggest that patients wear a medical alert bracelet and provide them with an appropriate action plan. An example of such a plan is available from the Food Allergy and Anaphylaxis Network. The purpose of the action plan is to outline the early signs and symptoms of a reaction, when it is appropriate to use antihistamines, when to use epinephrine and when to call 911. 



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Outgrowing food allergy


Tolerance is defined as either having naturally outgrown a food allergy or having received therapy so clinical symptoms no longer develop following ingestion of the food. In general, symptoms and exposure (accidental or not) are monitored over time. There are currently no specific recommendations for when to retest via SPT or ImmunoCAP levels.

However, many specialists will perform annual serum testing in children who have cow’s milk, egg, soy or wheat allergies because these are commonly outgrown by the age of 5 years. Testing for peanut, tree-nut, fish, and shellfish allergies may be performed every two to three years, as these allergies are typically not outgrown. Remember that these are not specific recommendations; rather, they represent the approach taken most commonly by allergists. 


The reason for retesting is to acquire data on specific IgE levels. With food allergies that are more commonly outgrown, the clinician will see a gradual decline in specific IgE levels over time. One may consider repeating an oral food challenge based on the lowered levels.

Rechallenge also might be considered when a child enters kindergarten. If the child has not already outgrown the allergy, parents may wish to know whether the youth will react if exposed to the food in question. In addition, the parent will have less control over what the child eats once he or she reaches school age, so a clearer understanding of what might happen upon exposure is key for both the child and the family. When considering whether or not to rechallenge a child, consultation with a provider who specializes in the treatment and management of food allergy is recommended.


Special considerations


Maternal diet, introduction of solids, and whether to breastfeed or bottle-feed are important issues to consider in the treatment and management of pediatric food allergy. Recommendations regarding maternal diet during pregnancy have changed over the years. The current recommendation is to not use restriction of maternal diet during pregnancy or lactation as a means of preventing food allergy.

Furthermore, there is no evidence to suggest that pregnant women should replace cow’s milk with soy milk to prevent food allergy in their newborn. Women wishing to breastfeed should do so for four to six months according to usual guidelines. Women who choose to bottle-feed should be encouraged to use a hydrolyzed infant formula (as opposed to cow’s milk) to help prevent development of food allergy in those infants at risk. With regard to solid food, there are no longer any recommendations to delay introduction. In fact, current guidelines suggest that even potentially allergenic foods may be introduced at the usual time solids enter the diet (age 4-6 months).


Primary-care clinicians often have questions about which immunizations can be safely administered to patients with food allergies. Even for patients allergic to egg, some egg-containing vaccines are safe to give in the primary-care setting. The measles, mumps, and rubella vaccine has been found safe even for those patients with severe egg allergy. However, other vaccines are contraindicated or may be used only after they have been “pretested.”

Currently, information is limited regarding the safety of administering the influenza vaccine in the primary-care setting. Influenza vaccine is recommended for those children most at risk for developing food allergy (e.g., children with asthma). In the high-risk child with egg allergy, a specialist should administer the influenza vaccine. While there are no current recommendations on exactly how to administer the vaccine, many specialists will perform SPT with the vaccine, and then split the dose in half, with each half administered separately. 


Yellow fever and rabies vaccines are contraindicated in egg-allergic patients.1

Lesser-known allergic entities must also be considered. Oral, or pollen-food, allergy syndrome is an IgE-mediated allergic disorder that is typically caused by a cross-reaction of food allergens with airborne allergens. Symptoms include mild pruritus, tingling, and/or angioedema of the lips, palate, tongue or oropharynx. Occasionally patients will complain of a sensation of tightness in the throat, but they rarely have systemic symptoms. Diagnosis is based on the clinical history and positive SPT responses to relevant food proteins.

Oral challenges have negligible value: Results are often positive when fresh foods are used but may be negative if the food is cooked. As an example, bananas and melons are related to each other and to ragweed. A patient who is allergic to ragweed may have oral symptoms after eating banana or melon. Because ragweed pollen peaks in the fall, patients may have more oral symptoms during that time. Another example is birch, which is structurally similar to several fruits and vegetables (e.g., carrot, celery, apple, pear, kiwi, potato). Therefore, patients allergic to birch may have oral symptoms of tingling and itching when they eat any of the related fruits and vegetables.9,10

Food-dependent exercise-induced anaphylaxis is defined as anaphylaxis with exercise following specific food ingestion. For example, the patient might follow a shrimp lunch with an afternoon jog that ends in an anaphylactic event. While relatively uncommon, this form of anaphylaxis is seen most often in adolescents and adults younger than age 40 years, although the age range may vary from younger than age 5 years to older than age 75 years.11,12 Females are more commonly affected than males. The mechanism is still unknown. The point of mentioning these disorders is to remind the clinician that a thorough history is key when evaluating a patient for food allergy. 


Referral 


While primary-care providers are certainly equipped with the knowledge to identify patients with food allergy, there are times when a specialist can be a valuable collaborator in providing the best care to patients and families. If the patient has severe or persistent disease, multiple food sensitivities or coexisting allergic disease, the specialist may be most able to identify the best diagnostic and treatment options. In addition, test interpretation can be just as complicated as performing food challenges.

The specialist often has easier access to dietitians and nutritionists who are experienced in the development of targeted elimination diets. And, as with all chronic disease, comprehensive patient education is extremely important. The specialist can reinforce the primary-care provider’s educational plan or offer education when time constraints limit the primary-care clinician’s ability to do so. 


Primary-care providers are frequently the first clinician to identify and treat food allergy. These clinicians must have a good understanding of what constitutes food allergy, what the different types of immunologic responses are, and who is at risk for developing food allergy. This information will allow the provider to complete a thorough history and physical examination as well as identify the most useful diagnostic studies.

Key to the patient’s success is an understanding of the illness, the importance of diet, and early treatment if there is a history of severe allergic reaction. Education and emotional support are also crucial. Pediatric food allergy can be challenging, but by working collaboratively with the family, nutritional experts, counselors and a specialist, care can be optimized. 


Cathy C. Ruff, MS, PA-C, is an associate professor in the Child Health Associate/Physician Assistant Program, Department of Pediatrics, University of Colorado at Anschutz Medical Center in Aurora. She practices clinically in the pediatric outpatient clinic at National Jewish Health in Denver.


References


1. Boyce JA, Assa’ad A, Burks AW et al. “Guidelines for the diagnosis and management of food allergy in the United States: summary of the NIAID-sponsored Expert Panel Report.” J Allergy Clin Immunol. 2010;126:1105-1118.


2. Rona RJ, Keil T, Summers C, et al. “The prevalence of food allergy: a meta-analysis.” J Allergy Clin Immunol. 2007;120:638-646.


3. American Academy of Allergy Asthma & Immunology. Allergy statistics.

4. Liu AH, Jaramillo R, Sicherer SH et al. “National prevalence and risk factors for food allergy and relationship to asthma: results from the National Health and Nutrition Examination Survey 2005-2006.” J Allergy Clin Immunol. 2010;126:798-806.


5. Eigenmann PA, Sicherer SH, Borkowski TA et al. “Prevalence of IgE-mediated food allergy among children with atopic dermatitis.” Pediatrics. 1998;101:E8.

6. Crespo JF, James JM, Fernandez-Rodriguez C, Rodriguez J. “Food allergy: nuts and tree nuts” Br J Nutr. 2006;96 Suppl 2:S95-S102.


7. Martelli A, De Chiara A, Corvro M et al. “Beef allergy in children with cow’s milk allergy; cow’s milk allergy in children with beef allergy.” Ann Allergy Asthma Immunol. 2002;89(6 Suppl 1):38-43. 


8. Sampson HA. “Update on food allergy.” J Allergy Clin Immunol. 2004;113:805-819.


9. Sloane D, Sheffer A. “Oral allergy syndrome.” Allergy Asthma Proc. 2001;22:321-325. 


10. van Ree R. “Clinical importance of cross-reactivity in food allergy.” Curr Opin Allergy Clin Immunol. 2004;4:235-240.


11. Morita E, Kunie K, Matsuo H. “Food-dependent exercise-induced anaphylaxis.” J Dermatol Sci. 2007;47:109-117.


12. Barg W, Medrala W, Wolanczyk-Medrala A. “Exercise-induced ­anaphylaxis: an update on diagnosis and treament.” Curr Allergy Asthma Rep. 2011;11:45-51.

All electronic documents accessed July 9, 2012.