Food Allergy
Definition |
Causes |
Risk Factors |
Symptoms |
Diagnosis |
Treatment |
Prevention |
Organizations
Definition
A food allergy is an adverse or abnormal reaction to a food or a food additive.
Causes
A few specific foods seem to cause a majority of the food reactions. The most likely triggers of a food reaction include:
- Peanuts
- Tree nuts (i.e., walnuts, pecans)
- Eggs
- Cow's milk and other dairy products
- Wheat
- Soy
- Shellfish and other seafood
- Tomatoes
- Fresh fruit, especially citrus, strawberries, melon
- Food dyes and chemical additives
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
- Age: young children
- History of eczema
- History of other types of allergies, including hay fever
Symptoms
Symptoms include:
- Gurgling stomach
- Stomach cramps, pain
- Nausea
- Vomiting
- Diarrhea
- Skin rash, especially hives
- Cough
- Wheezing
- Shortness of breath
- Swelling in lips, mouth, tongue, throat
- Nasal congestion
- Severe drop in blood pressure
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. Food allergies are often diagnosed based on your own observations of reactions to food or drink. It is a good idea to keep a diary of your symptoms, when they occur, and what you have eaten.
Tests may include:
Elimination Diet
You may be asked to go on an "elimination diet." Under your doctor's care, you do not eat a food that is suspected as the cause of your reaction. If your symptoms decrease or go away, your doctor can almost always make a diagnosis. If you eat the food and your symptoms come back, the diagnosis is confirmed. This method should not be used if symptoms are severe.
Scratch Skin Test
Your doctor can also use a scratch skin test. The doctor will put a dilute extract of the food on your forearm or back skin. If there is swelling or redness, an allergic reaction may be present. Using the results of the skin test in combination with your history of symptoms, the doctor will make the diagnosis. This test should not be used if you are severely allergic or have eczema.
RAST Or ELISA Test
In these cases, the doctor may order blood tests (RAST or ELISA). These tests measure the level of food-specific IgE in the blood. IgE is a type of protein that the body produces when it comes in contact with something to which it is allergic. The presence of IgE in the blood may indicate an allergy.
Treatment
Avoid foods and food ingredients that cause you to have an allergic reaction. If you think you've eaten something to which you are allergic, and you have difficulty breathing, call for emergency medical help immediately.
Treatments include:
- Antihistamine medication
- Epinephrine shot
- Corticosteroid medication
Prevention
To reduce your chance of having a food allergy reaction:
- Avoid eating/drinking substances to which you know you are allergic.
- Read the ingredient label on every food product that you eat.
- If you go to a restaurant, discuss your allergy with the food server and ask about all ingredients.
- Learn the chemical names for all your allergens so that you recognize them on an ingredients list.
- If you have a severe, anaphylactic-type food allergy, ask your doctor if you should carry a dose of epinephrine with you.
- Consider wearing a medical alert bracelet to inform others of your allergy.
Organizations
American Academy of Allergy, Asthma, and Immunology
http://www.aaaai.org/
Food Allergy and Anaphylaxis Network
http://www.foodallergy.org/
SOURCES:
Dambro: Griffith's 5-Minute Clinical Consult, 1999 ed. Lippincott Williams & Wilkins, 1999.
Middleton: Allergy: Principles and Practice, 5th ed. Mosby-Year Book, Inc, 1999.
Food Allergy and Anaphylaxis Network
National Institute of Allergy and Infectious Diseases
Last reviewed June 2001 by Medical Review Board
