Food Allergy – Atlanta, Peachtree City, Georgia
What is a Food Allergy?
A food allergy occurs when your body’s immune system overreacts to a protein in a certain food. In severe allergies, these reactions can be life threatening. The majority (90 percent) of food allergies are caused by eight foods: cow’s milk, eggs, fish, peanuts, shellfish, soy, tree nuts, and wheat.
Video Courtesy of American Academy of Allergy Asthma & Immunology
Click Here to read more about Food Allergies from the American Academy of Allergy Asthma & Immunology.
Food Allergy Versus Food Intolerance
Reacting to a food does not necessarily mean you are allergic to that food – you may just be intolerant to it. Food intolerance can cause similar symptoms to a food allergy, but food intolerance does not cause a full immune system response in your body. Food allergies cause an immune system response, and affect multiple organs. Generally, food intolerance causes less severe reactions, and may only cause digestive problems. People develop food intolerance for many different reasons, including lacking an enzyme necessary to digest the food, or having a sensitivity to additives in a food.
Article: Food Allergy Versus Food Intolerance
Ways to Diagnose a Food Allergy
- Skin Testing
During allergy skin testing, your skin is exposed to several allergens (food and/or environmental) and assessed for an allergic response. Your allergist will use a small plastic device to prick the skin and apply the allergens. If your skin becomes red, raised and itchy after 15-20 minutes, this may indicate an allergy.
- Allergy Blood Testing
Allergy blood tests are used if a patient can’t stop a medication that interferes with skin testing, if the patient has a skin condition like dermatitis, psoriasis or eczema, or if it would better suit the patient to have just one “poke” versus several (ie, a baby or young child). Blood testing is also used if the patient has poorly controlled asthma, or if the allergy is so severe that the testing could cause a systemic or anaphylactic reaction. Allergy blood tests are also used to check how well a patient’s allergy treatment is working.
Types of allergy blood tests include Enzyme-Linked Immunosorbent Assay (ELISA) and Radioallergosorbent Test (RAST). ELISA is used more commonly than RAST, and measures the amount of antibodies in your blood specific to certain allergens.
Complement testing can be used to measure the amount of a specific antibody or a specific antigen in the blood. The test helps determine which foods may be causing inflammation in the body and triggering an immune response.
- Oral Food Challenge
Double-blinded, placebo-controlled oral food challenge is considered the “gold standard” for food allergy diagnosis. This test is often used after skin prick testing and allergy blood testing fail to provide definitive results. In an oral food challenge, the patient is given very small amounts of a food that is suspicious for an allergy. Over a certain length of time, the amount of food is increased until any sign of an allergic reaction occurs. This test is always done under strict supervision of an allergist. The oral food challenge procedure can be costly and time consuming, however, so it is often not performed.
Delayed Food Allergy
Food allergy symptoms typically occur right after ingesting the responsible food, or at least within two hours. However, in a delayed response, the symptoms may take six or more hours to appear. These delayed responses can surface in different ways – such as a skin reaction from a food allergy, or a gastrointestinal reaction after ingesting milk or soy.
Patch Testing is a way to test for the allergens responsible for delayed allergic reactions. Instead of poking the skin with a plastic device to administer an allergen (as in allergy skin testing), patch testing occurs by placing a patch on a patient’s back that contains a small amount of the allergen. The patch stays on for two days, since a delayed allergic response will not occur quickly enough for skin prick testing. The patch site will be observed for redness, blisters, and swelling.
Sensitivity Testing is a blood test used to check for food sensitivities (different from food allergies). Food sensitivity is different from food allergy and food intolerance, and essentially describes an inconsistent and unpredictable reaction to certain foods. A person with food sensitivity may eat the food one time with no reaction, but experience symptoms (stomach cramps, nausea, acid reflux) at other times.