During allergy skin tests, your skin is exposed to suspected allergy-causing substances (allergens) and is then observed for signs of an allergic reaction.
Why is it done?
In general, allergy skin tests are performed for diagnosing allergies to airborne substances, such as pollen, pet dander, and dust mites
Are there risks?
- Skin tests are generally safe for adults and children of all ages, including infants.
- The most common side effect of skin testing is slightly swollen, red, itchy bumps (wheals) that may remain for a few minutes up to a couple of days.
- Rarely, allergy skin tests can produce a severe, immediate allergic reaction
- Your doctor may advise against skin testing if you:
- Have ever had a severe allergic reaction (anaphylaxis).
- Have certain skin conditions such as severe eczema or psoriasis
How do you prepare?
- Your doctor may ask that you stop taking certain medications for up to 10 days.
- Avoid applying excess cream or lotion to skin on a day of the test
What you can expect?
- Typically, this test takes about 15-30 minutes.
- A skin prick test, also called a puncture or scratch test, checks for immediate allergic reactions to as many as 50 different substances at once.
- In adults, the test is usually done on the forearm. Children may be tested on the upper back.
- Allergy skin tests aren’t painful. This type of testing uses needles (lancets) that barely penetrate the skin’s surface. You won’t bleed or feel more than mild, momentary discomfort.
- After cleaning the test site with alcohol, small marks are drawn on your skin and apply a drop of allergen extract next to each mark and prick the extracts with a lancet into the skin’s surface
- To see if your skin is reacting normally, two additional substances are scratched into your skin’s surface (Histamine and Glycerin or saline)
- About 15 minutes after the skin pricks, your skin is observed for signs of allergic reactions. If you are allergic to one of the substances tested, you’ll develop a raised, red, itchy bump (wheal) that may look like a mosquito bite.
- We will then measure the bump’s size and record the results. Next, your skin will be cleaned to remove the marks and apply cortisone cream to ease any residual discomfort.
Results are immediately available after completion of the test.
Skin prick test