Allergy Skin Tests
In general, skin tests for allergies are a good option choice because:
- The results are available immediately
- They can be more sensitive to subtle allergies
- They are less expensive
What are the different allergy skin tests?
1. Scratch (Puncture or Prick) Test
First, your health care provider examines the skin either on your forearm or back and cleans it with alcohol. Next, areas on your skin are marked with a pen to identify each allergen to be tested. A drop of extract for each potential allergen is placed on the corresponding mark. Now, a small disposable pricking device is used to prick the skin so the extract can enter into the outer skin layer. The skin prick is not a shot and does not cause bleeding. Lastly, the skin is closely watched for signs of a reaction, which include swelling and redness. Often such reactions occur in as little as 15 minutes.
2. Intradermal Test
First, your health care provider examines the skin either on your forearm or back and cleans it with alcohol. Then a small amount of the allergen is injected just under the skin. Lastly, you must wait about 15 minutes to see how your skin reacts.
3. Patch Test
The allergen is applied to a patch that is then placed on the skin. Sometimes, this is done to pinpoint a trigger of allergic contact dermatitis. If there are IgE’s (allergic antibodies) in your body, your skin will become irritated and may itch. This reaction means you are allergic to that substance. Patch tests take approximately 48 hours (do not bathe or swim while wearing these patches). You must return to your physician to determine whether your skin has reacted to the allergens.
Before your skin allergy test, your doctor will give you a list of medications to be avoided before the test since those drugs may interfere with the test. Specifically, allergy medicines, including over-the-counter antihistamines, stop allergic reactions, so you should not take them for 48 hours before the test. Speak to your doctor about discontinuing any allergy medicines or other medications prior to the test.
Content Created/Medically Reviewed by our Expert Doctors
