Accurate allergy testing allows patients to better understand and avoid their allergens. At Silver Falls Dermatology, our team offers various types of allergy testing to patients in Washington and Oregon.
Types of Allergy Tests
There are several types of allergy tests available. Choosing the best type for each patient largely depends on the type of allergen that is being tested for.
Skin Prick Test
Skin prick tests are also referred to as puncture or scratch tests. These tests are performed by applying a small amount of suspected allergens to the skin before pricking the skin’s surface using a lancet. This is minimally and momentarily uncomfortable and will not cause bleeding. The suspected allergens will then be left on the skin for 15 minutes, after which the area is observed for signs of an allergic reaction or wheal. Skin prick tests are typically used for common allergens including pollen, mold, animal dander, dust mites or some foods.
Skin Injection Test
A skin injection test is overall similar to a skin prick test. However, this test is performed by using a small needle to inject the suspected allergen just below the skin’s surface. It is also referred to as an intradermal test. Skin injection tests are most commonly performed to test for allergies to insects or penicillin.
A patch test is commonly performed to check for skin allergies or allergic contact dermatitis triggers. For example, a patch test might check for allergies to fragrances, preservatives, dyes, latex, medication or resins. These allergens often cause delayed reactions. For this reason, a patch test involves placing a patch containing the suspected allergens for 48 hours. During this time, it is important to avoid swimming, bathing or sweating.
Blood tests can be performed to check for allergen-specific antibodies in the blood. These tests are usually performed to check for the most common allergens, including dust, animal dander, pollens, mold or food allergies. Skin testing is much more commonly performed, but blood tests may be recommended for those who have severe reactions, skin conditions such as eczema or psoriasis or otherwise cannot tolerate a skin prick or injection test.
Food Allergy Tests
There are two common testing options specifically intended for food allergies. The first option is an elimination diet, in which the suspected allergen is removed from your diet for a set period of time, then reintroduced to observe symptoms. This is commonly used to test for allergies to wheat, dairy or other foods which can cause less severe reactions. An oral food challenge may also be recommended. This involves eating small amounts of the suspected allergen in gradually increasing doses within the controlled setting of your allergy and immunology provider’s office. Emergency medical care is available through the process in case of an anaphylactic reaction.
Preparing for Your Allergy Test
Some medications can interfere with allergy testing results. Prior to your test, you should disclose all of the medications you take with your provider. They will give you instructions regarding which medications to avoid the day of your allergy test. Some common examples include:
- Antihistamines (prescription or over the counter)
- Tricyclic antidepressants
- Heartburn medication
- Omalizumab (Xolair)