Food Allergies By Pat Bass, MD - Reviewed by a board-certified physician. Updated September 15, 2016 Food allergy is when your body has a specific and reproducible immune reaction to a food. Your body sees the ingested food as a threat and mistakenly treats it as a potential harmful substance, triggering a protective response.Food allergies impact 4 percent to 6 percent of children and about 4 percent of adults in the United States. This health concern tends to run in families, but your doctor will not be able to tell you if you or your child will have the same food allergy that, say, a sibling has. Common Signs & Symptoms of Food AllergyThose with food allergy often report abnormal sensations in their mouth, tongue, and throat including:Funny feeling of the tongue or mouth (for instance, a poking, jabbing, itchy, or heavy feeling, or as if there is hair present)Feeling like something is stuck in the throatFeeling of heaviness or thickness in the throatFeeling of a bump in throatJust because you experienced minimal or mild symptoms in reaction to a food today, that does not mean future reactions won't be more intense. Article Food Allergy versus Food Intolerance Article Allergic Reactions to Caffeine The most serious reaction to food is anaphylaxis. This is a life-threatening allergic reaction that can significantly impact your ability to breathe, drop your blood pressure, and alter your heart rate. Anaphylaxis can occur within minutes of exposure to the trigger food and, in some cases, can be fatal.Diagnosing Food AllergyYour doctor will ask you very detailed questions about the food you ate, when symptoms occurred in relation to when the food was ingested, as well as the specific symptoms experienced.Your doctor may order blood tests such as IgE levels or RAST tests. Specific testing for allergy to certain foods can be done with skin prick tests. Learn more about the diagnosis of food allergy.Common Causes of Food AllergyOver 90 percent of food allergy is caused by eight agents: Milk: Milk allergy is typically diagnosed in the first year of life, and most children outgrow this condition by age 5. It is the most common food allergy in American children. The allergy is to the milk proteins contained in casein and whey. This is different from lactose intolerance, which is due to an inability to digest carbohydrate in milk rather than an allergy. Eggs: Egg allergy is the second most common food allergy among kids. More than 80 percent will outgrow egg allergy before age 5. Some have a reaction to hidden egg ingredients. Soy: Food allergies to soy are generally mild, and most children outgrow this allergy in the first few years of life. However, reactions can be severe, and children allergic to soy also often have a milk allergy as well. Wheat: While adults are uncommonly allergic to wheat, 1 in 5 children allergic to wheat will also have an allergy to another grain. Children also commonly outgrow this allergy in the first few years of life. Article How Common is a Coffee or Caffeine Allergy? Article Meat Allergy Peanuts: This allergy is generally considered much more serious because rates of anaphylaxis are greater compared to other food allergies. One in 4 with peanut allergy also have a tree nut allergy. Tree nuts: Because this allergy often coexists with peanut allergy, you will also need to avoid peanuts if this affects you. While you can be allergic to just one tree nut, it is generally recommended that you avoid all tree nuts including walnuts, pecans, pistachios, hazelnuts, and almonds. Fish: This food allergy is more likely to develop as an adult. The most common offenders are salmon, tuna, and halibut. Like tree nuts, you can have an allergy to one fish and not others, but generally it is recommended that you avoid all fish. Shellfish: Similar to fish allergy, shellfish allergy is more common in adults. Both crustaceans and mollusks can lead to food allergy. These reactions also tend to be severe. While you can have a reaction to only one kind of shellfish, it is generally recommended that you avoid all shellfish. Thus, if you have a shellfish allergy, you need to avoid shrimp, crab, lobster, clams, oysters, mussels, and scallops. Food Allergy TreatmentFirst and foremost, you avoid eating your food allergy trigger. You will need to learn to read labels, ask about ingredients at restaurants, and make sure that you learn other names that the food you are allergic to can go by. You will also need to have a better understanding of where you food comes from. For example, though a dish you order may seem "safe," it may be prepared on the same surface as meals containing the food you are allergic to. The same goes for foods produced or packaged in plants that also make other products you may be allergic to. Ask questions. Do your research.The Food Allergy Labeling and Consumer Protection Act requires that food products be labeled in plain language—"contains milk," "contains soy"—to communicate ingredients. Many labels also warn of possible cross-contamination issues.Mild reactions such as itching, sneezing, hives, and rashes can be treated with antihistamines. Your doctor may also prescribe oral steroids if you develop a reaction. Article Allergy to Tequila, Beer and Wine Article Anaphylaxis After Eating Dust Mites The most serious reaction to food allergy, anaphylaxis, must be treated with an injection of epinephrine. Make sure that you know how to appropriately administer an epinephrine injector.Learn more about the treatment of food allergy.Can Food Allergies Be Prevented?Avoiding the introduction of solid foods before the age of 4 months may help prevent allergies, especially in families that are prone to food allergy. Additionally, delaying the introduction of highly allergenic foods such as peanuts, tree nuts, and seafood until after the age of 3 years may help prevent allergy to these foods. However, some more recent research examining if introduction of these foods in the first year of life may actually help prevent food allergy is beginning to challenge the more traditional approach to introducing these foods.Will My Child Outgrow Food Allergy?Children may outgrow their food allergies, but the answer depends on a number of factors. Peanut, tree nut, fish, and shellfish allergy tend to be lifelong, while children tend to outgrow milk, soy, egg, and wheat food allergies. It can be difficult to determine if your child will outgrow his or her allergy, or if it will persist. A low food specific IgE level seems to indicate a better chance of outgrowing an allergy.Learn more about the potential to outgrow food allergies.A Word From VerywellWhile diagnosing and managing food allergies can be a difficult and frustrating, food allergies do not have to rule your life. There will be changes in both diet and lifestyle, and these changes may impact others in your family. While it is normal to feel scared, challenged, or overwhelmed at the beginning, new routines and systems to keep yourself or your child safe while living with a food allergy will become routine and manageable. It is very important to increase your knowledge to learn not only how to avoid and prevent food allergy, is possible, but also the specific actions you must take if you develop symptoms.Sources: Boyce JA, Assa’ad A, Burks AW, et al; NIAID-Sponsored Expert Panel. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126(suppl 6):S1-S58. Branum AM, Lukacs SL. Food allergy among U.S. children: trends in prevalence and hospitalizations. NCHS Data Brief. 2008;10:1-8.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(4):798–806.e13.Practice Parameters for Allergy Diagnostic Testing. Ann Allergy Asthma Immunol. 1995; 75(6): 543–625.Sicherer SH. Food Allergies: A Complete Guide for Eating When Your Life Depends on It. 2013. The Johns Hopkins University Press. Baltimore, MD.