Woman with allergies sneezing and wondering how to test for allergies

How to test for allergies: a quick guide

Medically reviewed on July 13, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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Allergies are known to be the 6th most common cause of chronic illness in the US, ranging from severe tree nut allergies to mild seasonal hay fever. [1] But whether you’re trying to figure out what’s setting off your sniffles or which dinner party appetizer has left your stomach in knots, determining which substance is responsible for discomfort can be a challenge.

No matter what kind of allergy you suspect having, learning to live with an allergy always begins with proper testing. There are several diagnostic methods used to identify an allergy, and knowing which course of assessment to take is key to laying the foundation for treatment.

While there’s no cure for allergies, this guide will touch on each of the available allergy testing methods so that you can begin to make sound, informed decisions about your lifelong health.

Testing for food allergies

Food allergies affect an estimated 32 million Americans, with more than 170 different foods identified as potential allergens. [2] The most common food allergens include:

  • Eggs
  • Fish
  • Milk
  • Peanut
  • Shellfish
  • Soy
  • Tree nuts
  • Wheat

Allergic reactions to food substances range widely in severity, with symptoms ranging from mild discomfort, like throat itchiness, to potentially life-threatening. Food allergy symptoms usually arise within a few minutes to 1-2 hours following exposure to an allergen, though, in very rare instances, symptom onset can occur several hours after exposure. [3]

Typically, allergic reactions to food may be indicated by the following types of symptoms:

  1. Oral – Food allergens can cause a range of symptoms affecting your mouth, tongue, and throat. Itchiness or a tingling sensation in the mouth and swelling of the lips or tongue are all common oral symptoms of a food allergy.
  2. Cutaneous – As one of your immune system’s primary organs, skin reactions can also be a hallmark sign of a food allergy. Hives, rash, and itching are all common cutaneous symptoms. If you have an underlying skin condition (e.g. eczema), exposure to a food allergen may trigger a flare-up.
  3. Respiratory – In some cases, food allergens may cause throat swelling and airway constriction, making breathing labored or even cutting off your oxygen supply. Coughing, wheezing, and congestion may also accompany respiratory food allergy symptoms.
  4. Digestive – Many people experience digestive discomfort after ingesting a food allergen, from abdominal cramping to diarrhea. Nausea, vomiting, or loose stool may also accompany a food allergy.

A severe allergic reaction can lead to a very serious condition called anaphylaxis, where the immune system floods the body with chemicals like histamines in response to a perceived threat. [4] If left untreated, anaphylaxis can lead to anaphylactic shock, which can prevent the flow of oxygen, result in loss of consciousness, and even fatality. [4]

The potential for anaphylaxis is why food allergy testing is so important early on. Not only does knowing which foods trigger an immune response give you the tools you need to avoid them—it could even save your life.

Types of food allergy tests

Traditionally, food allergy testing has begun with a visit to your healthcare provider. They’ll run an initial assessment, beginning with:

  • Your self-reported symptoms and the foods you think may be causing them
  • A physical examination to rule out other conditions that could be causing your symptoms
  • A personal medical history including any food allergies that may run in your family. Some allergies have a genetic component, and knowing which ones you may have inherited can also help determine which kind of testing is best for you.

Following this initial screening, there are four main testing options that may be recommended to identify and diagnose a food allergy. These include: [5]

  • Skin prick test – During skin prick testing, a small amount of a substance containing the suspected allergen is placed on your skin. Your provider will gently prick your skin with a needle so that the substance enters your body. If you’re allergic to the substance, you’ll develop a small, red bump at the site of contact, usually within 20 minutes of exposure.
  • Blood test – Blood testing involves giving a sample of your blood and testing the reactivity of immunoglobulin E (IgE), an antibody the body produces to fight off substances it perceives as harmful. If your IgE levels heighten when exposed to a food substance, this may indicate the presence of an allergy.
  • Oral food challenge – This type of testing method involves ingesting small amounts of suspected allergens and monitoring your body’s physical response to them. Oral food challenges must always be supervised by a trained healthcare professional who can provide immediate treatment if necessary (this is especially important if you are suspected to have a severe food allergy).
  • Elimination diet – Elimination diets are a behavioral way of identifying foods that your immune system may not tolerate. They involve removing suspected allergens from your diet for a period of a few weeks, then gradually reintroducing them to gauge your immune system’s reaction. While this testing method is not considered an effective means of food allergy diagnosis, it can help to link your symptoms to specific allergens.

Testing for non-food allergies

While food allergies are one of the more common types of allergies to have, numerous other substances from latex to laundry detergent can also trigger an allergic reaction.

If you suspect having an allergy triggered by a substance other than food, one of the best testing methods to opt for is a skin test. Skin tests are used to identify and treat a range of allergic conditions, among them: [6]

  • Allergic asthma, which may be triggered by inhaling substances like pollen and dander.
  • Insect venom, which can indicate a reaction to stings from honeybees, yellow jackets, and wasps.
  • Dermatological conditions like atopic dermatitis or eczema, which have been associated with allergic reactions.
  • Hay fever, or allergic rhinitis, is commonly caused by pollen, dust mites, or animal dander (particularly during seasonal transitions).
  • Penicillin allergy, an allergy to the drug penicillin, which is used to treat a range of bacterial infections.

Types of skin testing

There are three primary skin testing methods used to screen for non-food allergies: [6]

  • Skin prick tests – In general, a skin prick test for non-food allergies is conducted the same way as it is for food allergies. Your skin is pricked, an allergen is introduced to the puncture, and you’re closely monitored to observe your body’s reaction to the substance.
  • Skin injection tests – Skin injection tests, also called intradermal tests, are a degree more invasive than a skin prick test. A small amount of an allergen substance will be injected beneath your skin with a needle, and a healthcare professional will observe your skin’s reaction. This type of test is commonly used to detect bee venom and penicillin allergies.
  • Patch tests – Patch testing is not as efficient as some other methods, but it can be useful in detecting allergies that cause dermatological symptoms—particularly those with delayed onset. In this method, you’ll wear an adhesive patch with a small extract of one or more allergens for approximately 48 hours and watch for any adverse reactions in your skin. Patch tests are commonly used to detect allergies to hair dyes, latex, fragrances, and metals.

Common treatments for allergies

Some allergens, like peanuts and animal fur, are easily avoidable with lifestyle and behavioral adjustments, while others (e.g. pollen) cannot be fully eliminated.

Fortunately, healthcare professionals have developed a host of chemical solutions that can help to make life safer and more manageable for people living with an allergy. Some common treatments for allergies include:

  • Antihistamines – Many antihistamines are available over-the-counter, while others require a prescription from your healthcare provider. Antihistamines work by impeding the effects of histamines, the chemicals your immune system releases that cause allergic symptoms like congestion, coughing, sneezing, and itchiness.
  • Epinephrine – Your medical provider may prescribe an epinephrine pen, or EpiPen, which is used to lessen the effects of severe allergic reactions like anaphylaxis. If you have a severe allergy, it’s essential to keep your EpiPen on hand at all times—this can help save your life if you’re exposed to an allergen.

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  1. Allergy Facts. American College of Allergy, Asthma, & Immunology. URL. Accessed July 13, 2022.
  2. The Food Allergy Epidemic. Food Allergy Research and Education. URL. Accessed July 13, 2022.
  3. Food Allergy – Symptoms and Causes. Mayo Clinic. URL. Accessed July 13, 2022.
  4. Anaphylaxis. Cleveland Clinic. URL. Accessed July 13, 2022.
  5. Food Allergy – Diagnosis and Treatment. Mayo Clinic. URL. Accessed July 13, 2022.
  6. Allergy Skin Tests. Mayo Clinic. URL. Accessed July 13, 2022.
  7. Antihistamines. Cleveland Clinic. URL. Accessed July 13, 2022.
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