Food Allergy
A food allergy is an abnormal immune system reaction to certain foods that can range from mild to life-threatening.
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. While an intolerance may cause digestive symptoms such as bloating and gas, it is not an immune system reaction.
Common Food Allergens
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
Who is more likely to develop a food allergy?
Both children and adults can have food allergies. Some children will outgrow their food allergies, while others may develop them as adults. Certain factors increase the likelihood of having a food allergy:
- Having eczema: A disease that causes inflammation, redness, and irritation of the skin.
- 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 them if someone in your family has allergies, asthma, or eczema.
Symptoms
Food allergy symptoms usually start within a few minutes to two hours after you eat the 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
Anaphylaxis
In rare cases, a food allergy can cause a life-threatening reaction called anaphylaxis. This is a medical emergency. Call 911 if someone experiences:
- 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
Diagnosis
To find out if you have a food allergy, your health care provider will:
- Ask about your symptoms, family health history, and medical history.
- Likely do a physical exam.
- Perform food allergy testing, which could involve skin testing, blood testing, a food elimination diet, and/or an oral food challenge test, which is the most accurate test.
Treatment
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. Medicines include:
- Antihistamines and corticosteroids to reduce symptoms.
- Medicines to reduce allergic reactions.
- Epinephrine: A medicine to treat anaphylaxis. Your provider may give you a prescription for an epinephrine auto-injector. It is important to learn how to use it and 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.