Food allergies are becoming increasingly common, with an estimated 30 million Americans having one. There are several ways to test for a food allergy, and sometimes, a combination of tests may be required to accurately diagnose an allergy.
What Is a Food Allergy?
The immune system is the body’s defense against infection and disease. A food allergy occurs when your immune system overreacts to specific food and mistakenly sees it as a threat, causing a number of chemicals to be released, which trigger the symptoms of an allergic reaction. Virtually any food can trigger an allergic reaction, but there are certain foods that more commonly cause food allergies, which include:
- Cow’s milk
- Tree nuts (almonds, walnuts, pecans, cashews, pistachio, hazelnuts)
- Fish and/or shellfish
- Some types of fruit and vegetables
Food Allergy Symptoms
Common symptoms of a food allergy include:
- A raised itchy, red rash known as hives (or urticaria)
- Swelling of the face, primarily the lips and tongue
- Sensation of itchiness in the mouth, throat, or ears
- A runny nose or congestion
- Nausea or vomiting
- Coughing and/or wheezing
In very serious cases, a severe allergic reaction can cause anaphylaxis. This is a life-threatening condition, and symptoms typically occur within minutes of allergen exposure. It can cause swelling of the airway leading to breathing difficulties, trouble speaking or swallowing, dizziness or fainting, and symptoms of shock due to low blood pressure.
Diagnosing A Food Allergy
If you suspect a food allergy, it is important to be evaluated by an allergist for accurate diagnosis. There are a variety of allergy testing methods to diagnose a food allergy, including skin, blood, and food tests.
Diagnosing a food allergy begins with a thorough evaluation of your family and medical history. A family history of hay fever, asthma, eczema, or any allergic disease can be risk factors for a food allergy. Your allergist will also ask for a detailed review and history your symptoms, such as which foods are suspected to cause a reaction, severity of symptoms, how quickly symptoms start after exposure to the food, and how long they last.
A skin test may be used to determine a reaction to a particular food and is carried out using the skin prick test. It requires a small amount of the suspected allergen to be placed on the skin (usually on the forearm). The skin is then pricked with a small needle to allow a tiny amount of the substance to come into contact with cells of the immune system beneath the skin’s surface. Itching, redness, and swelling typically indicate an allergic reaction to the substance.
Immunoglobulin (IgE) blood tests are another form of allergy testing that measure the amount of allergy-related (IgE) antibodies in the blood. High levels may indicate an allergic reaction to specific substances.
Oral Food Challenge
An oral food challenge (also called a feeding test) may be used to diagnose a food allergy. The test involves slowly eating foods suspected of causing symptoms while in a doctor’s office and under medical supervision. This ensures prompt and appropriate medical treatment in the event of an allergic reaction. The test is considered safe and can be more reliable than skin or blood tests to confirm food allergies.
An elimination diet may be carried out to help link symptoms to specific foods. It involves eliminating suspect foods for a period of time and then reintroducing them back into your diet one at a time to identify which food is causing symptoms. The elimination diet is not recommended if a severe allergic reaction has been experienced previously.
Once allergy testing has been completed, your allergist will review the results with you and discuss the different treatment options. An allergy test can be an effective way to pinpoint the precise type of food allergy involved, but a positive test alone does not confirm a diagnosis of food allergy. An allergist can work with you to develop a customized food allergy action plan to help ensure as healthy, safe, and normal of a lifestyle as possible. Food allergies can change over time, so it is important to follow up regularly with your allergist for any modifications to medications or other treatment approaches.
Food Allergy Testing in Will County & DuPage County, IL
If you or a member of your family has a suspected food allergy, the providers at Oak Brook Allergists are happy to help. We are the leading experts in the Chicago area in the diagnosis and treatment of many different types of food allergies. To find out more about the services and treatments we provide, call us today at (630) 574-0460 or you can request an appointment online now.