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Summary
What is a food allergy?
A food allergy is an abnormal immune system reaction to certain foods. Your immune system normally protects you from germs. But if you have a food allergy, your immune system mistakenly reacts to certain foods as if they were harmful. This reaction is usually mild. But in some cases, it can be serious or even life-threatening.
A food intolerance is different than a food allergy. If you have a food intolerance, you also have symptoms when you eat that food. But these are typically just digestive symptoms such as bloating and gas. Also, an intolerance is not an immune system reaction.
Most food allergies are caused by:
- Cow's milk
- Chicken eggs
- Crustacean shellfish, such as shrimp, crab, lobster, and crayfish
- Fish
- Peanuts
- Sesame
- Soy
- Tree nuts, such as almonds, walnuts, pecans
- Wheat
People with a food allergy may be allergic to more than one type of food.
Who is more likely to develop a food allergy?
Both children and adults can have food allergies. Some children will outgrow their food allergies. And sometimes people can develop food allergies as adult.
Certain factors can make you more likely to have a food allergy. They include:
- Having eczema, a disease that causes inflammation, redness, and irritation of the skin. Your immune system also plays a role in eczema.
- Having asthma or other allergies, such as hay fever.
- Your genes. Certain genes may influence the development of food allergies. And you are more likely to have food allergies if someone in your family has allergies, asthma, or eczema.
What are the symptoms of food allergies?
If you are allergic to a food you have eaten, you may have a variety of symptoms. These symptoms are not always the same for every person. And the symptoms that you get each time you eat the food may not always be the same. For example, your symptoms may sometimes depend on how much of the food you ate.
Food allergy symptoms usually start within a few minutes to two hours after you eat that food. They may include:
- Hives
- Flushed skin or rash
- Tingling or itchy sensation in the mouth
- Face, tongue, or lip swelling
- Vomiting and/or diarrhea
- Abdominal (belly) cramps
- Coughing or wheezing
- Dizziness and/or lightheadedness
- Swelling of the throat and vocal cords
- Trouble breathing
In rare cases, a food allergy can cause a life-threatening reaction called anaphylaxis. It may start out with some milder symptoms, but then it becomes more serious. It can lead to:
- Narrowed airways in the lungs
- Severe trouble breathing because of swelling in the throat
- Severe lowering of blood pressure and shock ("anaphylactic shock")
- Loss of consciousness
This is a medical emergency. Call 911 if someone is having the symptoms of anaphylaxis.
How are food allergies diagnosed?
To find out if you have a food allergy, your health care provider will
- Ask about your symptoms, family health history, and medical history, including other allergies.
- Likely do a physical exam.
- Do food allergy testing. This could involve skin testing, blood testing, a food elimination diet, and/or an oral food challenge test. An oral food challenge test is the most accurate food allergy test.
What are the treatments for food allergies?
There is no cure for food allergies. The only way to prevent a reaction is to avoid eating the food that you are allergic to.
There are medicines for people with food allergies. They include:
- Medicines to reduce food allergy symptoms, including antihistamines and corticosteroids.
- Medicines to reduce allergic reactions, including severe reactions.
- Epinephrine, a medicine to treat anaphylaxis. Your provider may give you a prescription for an epinephrine auto-injector. It is a device used to inject epinephrine when someone is having symptoms of anaphylaxis. If you have been prescribed one, it's important to learn how to use it and to carry it with you at all times.
If you have a food allergy, it's a good idea to have a medical alert bracelet that says what your allergy is.
Diagnosis and Tests
- Allergy Blood Test (National Library of Medicine) Also in Spanish
- Food Allergy Testing (National Library of Medicine) Also in Spanish
- Reasons to Do Food Challenges (National Jewish Health)
Treatments and Therapies
- Recognizing and Treating Reaction Symptoms (Food Allergy Research & Education)
Living With
- Avoiding Cross-Contact (Food Allergy Research & Education)
- Dining Out (Food Allergy Research & Education)
- Have Food Allergies? Read the Label (Food and Drug Administration) Also in Spanish
- Living with Food Allergies (Food Allergy Research & Education)
- Managing Food Allergies at College (Food Allergy Research & Education) - PDF
- Taking Care of Yourself (Food Allergy Research & Education)
- Tips for Keeping Safe at Home (Food Allergy Research & Education)
- Traveling with Food Allergies (Food Allergy Research & Education)
Related Issues
- Eosinophilic Esophagitis: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
- Food Intolerance vs. Food Allergy: What's the Difference? (Mayo Foundation for Medical Education and Research) Also in Spanish
Specifics
- About Alpha-gal Syndrome (Centers for Disease Control and Prevention)
- Egg Allergy (Nemours Foundation) Also in Spanish
- Fish Allergy (Nemours Foundation) Also in Spanish
- Fish Allergy (Food Allergy Research & Education)
- Milk Allergy (Food Allergy Research & Education)
- Milk Allergy (Mayo Foundation for Medical Education and Research) Also in Spanish
- Peanut Allergy (Food Allergy Research & Education)
- Peanut Allergy (Mayo Foundation for Medical Education and Research)
- Shellfish Allergy (Nemours Foundation) Also in Spanish
- Shellfish Allergy (Food Allergy Research & Education)
- Soy Allergy (Food Allergy Research & Education)
- Tree Nut Allergy (Food Allergy Research & Education)
- Wheat Allergy (Food Allergy Research & Education)
- Wheat Allergy (Mayo Foundation for Medical Education and Research) Also in Spanish
Videos and Tutorials
- Histamine: The Stuff Allergies are Made of (National Library of Medicine) Also in Spanish
Test Your Knowledge
- Test Your Food Allergy Knowledge (Medical Encyclopedia) Also in Spanish
Statistics and Research
- Facts and Statistics about Food Allergies (Food Allergy Research & Education)
- Food Allergy (National Institute of Allergy and Infectious Diseases)
- Lasting Protection From Peanut Allergy (National Institutes of Health) Also in Spanish
- Understanding Food Allergies: How to Prevent Peanut Allergy and More (National Institutes of Health) Also in Spanish
Clinical Trials
- ClinicalTrials.gov: Egg Hypersensitivity (National Institutes of Health)
- ClinicalTrials.gov: Food Hypersensitivity (National Institutes of Health)
- ClinicalTrials.gov: Milk Hypersensitivity (National Institutes of Health)
- ClinicalTrials.gov: Nut Hypersensitivity (National Institutes of Health)
- ClinicalTrials.gov: Peanut Hypersensitivity (National Institutes of Health)
- ClinicalTrials.gov: Wheat Hypersensitivity (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Characterization of the Gut and Skin Microbiome over Time in Young...
- Article: Adaptation of the ''Food Allergy Self-Efficacy Scale for Parents''(FASE-P) to Turkish:...
- Article: Interpreting epidemiologic distribution of total and specific IgE levels for food...
- Food Allergy -- see more articles
Find an Expert
- Find an Allergist/Immunologist (American Academy of Allergy, Asthma, and Immunology)
- National Institute of Allergy and Infectious Diseases
Children
- Allergies and Hyperactivity (American Academy of Pediatrics) Also in Spanish
- Asthma and Food Allergies (American Academy of Pediatrics) Also in Spanish
- Dairy-Free Diet (For Parents) (Nemours Foundation) Also in Spanish
- Food Allergies (Nemours Foundation) Also in Spanish
- Food Protein Induced Enterocolitis Syndrome (FPIES) (Nemours Foundation) Also in Spanish
- Infant Allergies and Food Sensitivities (American Academy of Pediatrics) Also in Spanish
- Milk Allergy in Infants (Nemours Foundation) Also in Spanish
- Nut and Peanut Allergy (Nemours Foundation)
- Tree Nut Allergy (Nemours Foundation) Also in Spanish
- Tree Nut Allergy (For Parents) (Nemours Foundation) Also in Spanish
Teenagers
- Egg Allergy (Nemours Foundation)
- Food Allergies (Nemours Foundation) Also in Spanish
- Food Allergies in Schools (Centers for Disease Control and Prevention)
- Milk Allergy (Nemours Foundation)
- Nut and Peanut Allergy (Nemours Foundation) Also in Spanish
- Tree Nut Allergy (Nemours Foundation) Also in Spanish
Patient Handouts
- Allergy testing - skin (Medical Encyclopedia) Also in Spanish
- Anaphylaxis (Medical Encyclopedia) Also in Spanish
- Food allergy (Medical Encyclopedia) Also in Spanish