Family Health|Food and Nutrition|Infants and Toddlers|Kids and Teens|Prevention and Wellness
allergy|Allergy and Immunologic

Food Allergies

Last Updated January 2023 | This article was created by editorial staff and reviewed by Robert "Chuck" Rich, Jr., MD, FAAFP

What is a food allergy?

A food allergy is an abnormal reaction by your immune system to a food. The immune system is the part of your body that fights infection. The reaction can be mild or serious. Food intolerance is different than a food allergy. Food intolerance is an unpleasant symptom triggered by food (bloating, gas, stomach cramps). However, it doesn’t involve your immune system.

Symptoms of a food allergy

Symptoms of a food allergy are usually immediate. The most common symptoms of food allergy include:

  • Hives (large bumps on the skin)
  • Swelling
  • Itchy skin
  • Itchiness or tingling in the mouth
  • Metallic taste in the mouth
  • Coughing, trouble breathing, or wheezing
  • Throat tightness
  • Cramps in your abdomen
  • Diarrhea
  • Vomiting

The person may also feel something bad is going to happen. They may have pale skin (because of low blood pressure) or lose consciousness. They may also have chronic illnesses. Eczema (skin disorder) and asthma (respiratory disorder) are the most common.

A food allergy can be deadly if it’s severe enough to cause a reaction called anaphylaxis. This reaction blocks your airway and makes it hard to breathe.

What causes food allergies?

Although people can be allergic to any kind of food, most food allergies are caused by tree nuts, peanuts, milk, eggs, soy, wheat, fish, and shellfish. These 8 foods account for 90 percent of food allergies. Most people who have food allergies are allergic to fewer than four foods.

Additionally, studies have found that some food additives, such as yellow food dye and aspartame (artificial sweetener), cause problems in some people. Sugar and fats aren’t associated with food allergies.

How are food allergies diagnosed?

If you’ve had an abnormal reaction to a food, see your doctor. They will examine your symptoms and ask about your health history. Your doctor may put you on an elimination diet. This is when you don’t eat any suspicious foods for a while then gradually add them back one at a time. Your doctor also may perform skin and blood tests, though these are not as reliable as the elimination diet.

Many children usually outgrow allergies to milk, eggs, soybean products, and wheat. People rarely outgrow allergies to peanuts, tree nuts, fish, and shellfish.

Can food allergies be prevented or avoided?

Recent studies have found that some food allergies – such as peanut allergies – can be prevented if they are treated at an early age. The National Institute of Allergy and Infectious Diseases recommends that infants with severe eczema, egg allergy or both be introduced to foods containing peanuts as early as 4 months of age to reduce the risk of a peanut allergy. Talk to your doctor before introducing foods containing peanuts at this early age.

Once a food allergy is diagnosed, avoid the food that cause it. If you have an allergy, you must read the labels on all prepared foods you eat. Your doctor can help you learn how to avoid eating the wrong foods. If your child has food allergies, give his or her school and other care providers instructions of what foods to avoid. Tell them what to do if the food is accidentally eaten.

Food allergy treatment

While there is no cure for a food allergy, there are new therapies that increase tolerance to food items so that if you accidentally eat something you are allergic to your body might not have an extreme reaction.

If you have a mild reaction (itching, sneezing, hives, or rash), your doctor will give you antihistamines and oral or topical steroid medicine. A severe reaction of anaphylaxis is treated with a medicine called epinephrine. This medicine must be given quickly to save your life. If you or your child has a severe allergy, your doctor may give you a prescription for an epinephrine pen to carry at all times. Your doctor or pharmacists can show you how and when to use the pen. A person having a serious allergic reaction should be taken by ambulance to a hospital emergency room.

Living with food allergies

Living with food allergies can cause fear and anxiety when you’re eating at a restaurant or someone else’s home. You will always wonder if your problem food is combined with the rest of the meal. Also, if you have food allergies to most of the 8 common foods, you can feel frustrated by the restrictions in your life.

Questions to ask your doctor

  • How should I handle having a food allergy reaction?
  • Is the first bad reaction usually mild or severe?
  • Are food allergies inherited?
  • Do symptoms appear in a certain order to give you some warning?
  • Can you develop food allergies later in life?
  • Can peanut allergies be prevented in infants?
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