Tuesday, December 4, 2012

Food Allergy Guidelines in Kids

Food Allergies in Kids: Putting the Guideline Into Practice

An Expert Interview With AAAAI

Laurie Scudder, DNP, PNP, Anna Nowak-Wegrzyn, MD
  Nov 27, 2012 Authors & Disclosures
Editor's Note:
In 2010, an expert panel convened by the National Institute of Allergy and Infectious Diseases (NIAID) released Guidelines for the Diagnosis and Management of Food Allergy in the United States[1] This exhaustive summary of current literature and expert opinion provided 43 clinical recommendations for the recognition and management of the growing problem of food allergies. One year later, a second group of pediatric allergy experts provided a summary that described the application of these guidelines in infants, children, and teens. [2] However, the American Academy of Pediatrics (AAP) Section on Allergy and Immunology recognizes that more education and awareness are necessary to insure widespread uptake of the guidelines. To that end, AAP and the American Academy of Allergy, Asthma & Immunology (AAAAI) have developed summary documents for pediatric and family medicine providers. Medscape spoke with Anna Nowak-Wegrzyn, MD, Associate Professor of Pediatrics at Mount Sinai School of Medicine's Jaffe Food Allergy Institute about the AAP/AAAAI efforts, the most relevant guidance for children, and continuing controversies in the area of food allergies.
Medscape: What has been the reaction to the guidelines on the part of pediatric providers?
Dr. Nowak-Wegrzyn: I would say overwhelmingly positive. The guidelines were welcomed because food allergy is very common in pediatric practice and not easy to diagnose and manage. Having a document that provides some benchmarks and concrete advice is very helpful.
Medscape: What are the major differences between the 2010 guidelines and earlier recommendations from AAP?
Dr. Nowak-Wegrzyn: The 2010 guidelines put all the current standards of practice into 1 document. In fact, the guidelines reiterated some of the previous guidelines issued by AAP. For instance, the AAP Section on Allergy and Immunology guidelines on prevention of food allergy through diet [3] have been in agreement with the guidelines. Another recent document on use of allergen-specific IgE testing in children with suspected food allergy [4] is well aligned with the guidelines.
Medscape: Are there specific recommendations that have been more challenging to implement in kids?
Dr. Nowak-Wegrzyn: Defining the role of food allergy in children who have atopic dermatitis remains quite challenging. The guideline states that children who have moderate to severe persistent atopic dermatitis benefit from an evaluation for food allergies; it is definitely a clinically challenging problem to figure out which children are appropriate for this kind of evaluation.
The other area of controversy is food allergy prevention by dietary modification; the question of whether avoidance of certain foods during pregnancy or early life could modify the natural course of allergy or prevent food allergy continues to be investigated. The guideline states that there is really no evidence to recommend any of these interventions and emphasizes that the preferred nutrition for an infant is breastfeeding in the presence of a healthy, unrestricted maternal diet. Solids should be introduced when children are ready for the different textures, which usually happens between 4 and 6 months of age. There is really no evidence that delaying introduction of any highly allergenic foods beyond that point prevents any allergy.
This is, again, aligned with the prior statements that were issued by the AAP Section on Allergy and Immunology regarding that topic.
Medscape: Subsequent to the publication of the NIAID-sponsored guideline, the AAP Section on Allergy and Immunology released a clinical report describing the use of allergen-specific IgE testing in children suspected of food allergy. [4] Can you describe the key elements of this report for primary care pediatric providers? Are they in alignment with the 2010 guidelines?
Dr. Nowak-Wegrzyn: Yes. This report is really a reiteration of the guidelines and emphasizes that IgE food allergy represents a big portion of food allergy disorders. These include anaphylaxis, immediate urticaria, and angioedema, as well as atopic dermatitis in some children. Testing for food-specific IgE, which can be done by measurement of specific IgE in the serum or skin-prick testing, is the currently available mainstay of diagnosis. These 2 methods of testing have similar sensitivity and specificity; however serologic testing has less variability.
Both documents caution about careful interpretation of those test results, because documenting a positive IgE response to food doesn't equate to diagnosis of food allergy. Many children who have positive skin tests and positive detectable IgE levels to specific food can ingest the food without any symptoms; in such situations as this, food challenges might be necessary to provide an accurate diagnosis.
In contrast, the documents advise caution even if the tests are negative. That is, even if the child has an undetectable level of IgE by skin-prick test or blood measurement but he or she has a history of an anaphylactic reaction after ingestion of a certain food, the guidelines say you have to take a step back. You cannot just say, well, this child is no longer allergic to this food and allow him or her to eat it at home. If you have a history of severe reaction, even in the setting of negative testing, you should definitely recommend a supervised oral food challenge by a physician who is familiar with managing anaphylaxis.
On one hand, there are children with positive testing who eat the food without any symptoms and nothing happens. On the other hand, there are children who have negative tests, and yet they have a history of severe reactions. In both situations, you have to be pretty careful in interpreting those results.
The other thing that the guidelines stress, which I think is very important for a pediatric provider to recognize, is not to perform panel testing of large panels of food allergens. Instead, focus on the major food allergens in childhood, which are cow's milk, egg, soy, wheat, fish, and peanut and tree nuts. For example, take the case of a child who has severe atopic dermatitis that is very difficult to control with medical therapy, and you are considering the possibility of a food allergen being responsible for this child's skin symptoms. It is appropriate to test for these most common offenders, in addition to the specific foods that have a clear history of a reaction.
The diagnosis of food allergies is not casual. It changes everything. It changes the child's nutrition and increases the potential for a resultant deficiency of protein, vitamins, and minerals. On the other hand, if you miss the diagnosis there is the risk for a life-threatening reaction. Diagnostic accuracy is extremely important. You really don't want to run a panel of 50 tests and then say to the child and family: You are positive, and you are allergic to those 50 foods -- avoid them, goodbye.
If you have reasons to believe that the child with severe atopic dermatitis that is not well controlled with the optimal medical therapy, including moisturizing skincare and moderate- to high-potency topical steroids or anti-inflammatories (such as tacrolimus or pimecrolimus), has an allergy that is driving the skin inflammation, you should look at milk, egg, soy, wheat, or nuts as the most likely causes of skin disease. You would definitely want to perform food challenges to prove that avoidance is necessary. However, if the test results are within the highly predictive range in a child (eg, peanut IgE level ≥ 15 kIU/L), you have over 95% certainty that this child would react with some kind of a symptom during the food challenge test, so you might delay the feeding (challenge) test.
Although as clinicians, we focus on avoidance in kids with food allergies, it is equally important to ensure that you are also making up for things that you are taking away from them. They should be referred to a nutritionist or a dietician to correct for those deficiencies.
Medscape: Can you speak to the emotional effect of food allergy on a young child ?
Dr. Nowak-Wegrzyn: You bring up a very important point. As a physician, I typically focus on the medical issues, such as risk for anaphylaxis or severe eczema. But this diagnosis, as you well know, affects the entire family.
Food allergies affect quality of life not only for an individual child, but also the entire family. It affects how the parents live and cook, where they shop, and where they go out -- or maybe they stop going out, because they don't want to go to a restaurant and be at risk for a reaction. Some people will not fly. They will not go on vacation to a remote area with a child with this diagnosis.
Food allergy is not a casual diagnosis. It has to be really taken seriously. Overdiagnosing food allergy has multifaceted implications for the child and the family.
Medscape: The expert panel in 2010 concluded that insufficient evidence existed to recommend administering influenza vaccine, either inactivated or live-attenuated, to patients with a history of severe reactions to egg proteins. Subsequent guidance from the Advisory Committee on Immunization Practices (ACIP) notes that persons experiencing severe reactions to egg should be referred to an allergist for further testing, but did not indicate that vaccination was contraindicated. [5] This issue continues to be a concern to practicing clinicians. Can you summarize the current evidence on administration of influenza vaccine to children with suspected egg allergy?
Dr. Nowak-Wegrzyn: The guidelines were based on the evidence that was published before they were issued in 2010. Since then, a number of clinical reports and large studies have reported safe administration of the influenza vaccine to children with egg allergy.
What also happened over that period is that the production standards have changed. The industry recognized that this is an issue for many children and improved methods to lower the content of egg proteins, and most vaccine manufacturers now provide information about the content of ovalbumin.
Medscape: A recent study conducted by researchers at the Mayo Clinic documented a 3-fold increase in the incidence of peanut allergy in children[6] Over three quarters of these cases occurred in children younger than 2 years, and about 70% were boys. Can you speak to some of the potential reasons for this increase?
Dr. Nowak-Wegrzyn: This is the million-dollar question! There are many hypotheses. For one, the phenomenon of peanut allergy epidemics is happening mostly in highly developed countries with a so-called westernized lifestyle. In these countries, peanut is predominantly consumed in dry-roasted form. In the other 2 top producers and consumers of peanut, China and India, peanut is consumed as peanut oil or fried or boiled peanut. Studies have shown that the high temperatures during dry roasting make certain proteins more resistant to digestion and enhance the allergenic properties of peanut.
The timing of the introduction of peanut into the infant's diet may be also important. The peanut epidemics unfolded in countries that adopted delayed introduction of peanut into the diet, beyond the first 2-3 years of life, as a means of preventing peanut allergy in susceptible children. However, when 2 Jewish populations were compared -- one living in London that had high rates of peanut allergy, and the other living in Israel that had very low rates of peanut allergy -- the only difference identified was the timing of introduction peanut to infant diet. [7] In London, peanut introduction was delayed, whereas in Israel, peanut was introduced early -- usually by 6 months of age -- in a form of a corn puff covered with peanut, which is a popular snack in that country. This observation led to a very important study,Learning Early About Peanut Allergy (LEAP), that is currently being conducted in London. In this study, children at risk for peanut allergy are being exposed to peanut early in life. The results are expected in 2013-2014.
These are only 2 examples; other theories include the hygiene hypothesis or an overall change in the diet toward more saturated fatty acids.
Medscape: Can you describe the AAAAI and AAP outreach efforts and point our members to best available clinical resources?
Dr. Nowak-Wegrzyn: Both organizations have been very proactive in exploring every possible means of disseminating the guidelines. We have contacted other professional organizations to feature articles in their journals. There were articles that targeted only some aspects of the guidelines, such as the previously mentioned article by Drs. Sicherer and Wood from the Section on Allergy and Immunology on allergy testing in childhood using allergen-specific IgE tests. [4] The Adverse Reactions to Food Committee of the AAAAI developed brief summaries emphasizing the most important guidelines for pediatric as well as internal and family medicine practitioners. These summaries can be freely accessed at the AAAAI website.
Most important, the complete food allergy guidelines can be accessed free of charge online, as canexecutive summaries for clinicians, patients, and families.
Medscape: Any concluding advice for our members?
Dr. Nowak-Wegrzyn: I urge my colleagues to take advantage of the guidelines to get care for children with food allergy up to speed. Think about food allergy in children, because it is a common disorder, affecting about 6%-8% of children in the United States. Always listen carefully to your patients, but remember that the most common food allergies are to cow's milk, hen's egg, peanut, tree nuts, soy, wheat, and seafood. Therefore, avoid fishing expeditions and testing for large panels of food allergens. The younger the child, the more important is the nutritional evaluation to avoid deficiencies. Finally, in children with a history of food-induced anaphylaxis, multiple food allergies, or reactions from unknown food triggers, consider consulting with an allergist.