Schedule an Allergy Skin Test

During allergy skin tests, your skin is exposed to suspected allergy-causing substances (allergens) and is then observed for signs of an allergic reaction.

Along with your medical history, allergy tests may be able to confirm whether a particular substance you touch, breathe or eat is causing symptoms. service.

Information from allergy tests may help our provider develop an allergy treatment plan that includes allergen avoidance, medications, sublingual immunotherapy (drops) or allergy shots (immunotherapy).

Allergy skin tests are widely used to help diagnose allergic conditions, including:

• Hay fever (allergic rhinitis)
• Allergic asthma
• Dermatitis (eczema)
• Food allergies
• Bee venom allergy (blood test may be required)

Skin tests are generally safe for adults and children of all ages, including infants. In certain circumstances, though, skin tests aren't recommended. Our provider will go over these situations with you in detail at your consult. 

The most common side effect of skin testing is slightly swollen, red, itchy bumps (wheals). These wheals may be most noticeable during the test. In some people, though, an area of swelling, redness and itching may develop a few hours after the test and remain for a couple of days.

Rarely, allergy skin tests can produce a severe, immediate allergic reaction, so it's important to have skin tests performed at an office where appropriate emergency equipment and medications are available.

Before scheduling a skin test, we will review a list of all of your prescription and over-the-counter medications. Some medications can suppress allergic reactions, preventing the skin testing from giving accurate results. Other medications may increase your risk of developing a severe allergic reaction during a test.

Because medications clear out of your system at different rates, our provider may ask that you stop taking certain medications for up to 5-10 days. Medications that can interfere with skin tests include:

• Prescription antihistamines, such as hydroxyzine (Vistaril).
• Over-the-counter antihistamines, such as loratadine (Claritin, Alavert), diphenhydramine (Benadryl), chlorpheniramine, cetirizine (Zyrtec Allergy) and fexofenadine (Allegra).
• Tricyclic antidepressants, such as nortriptyline (Pamelor) and desipramine (Norpramin).
• Certain heartburn medications, such as cimetidine (Tagamet) and ranitidine.
• The asthma medication omalizumab (Xolair). This medication can disrupt test results for six months or longer even after you quit using it. For comparison, most medications affect results for days to weeks.

Please call us with any specific questions or concerns. 

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. This test is usually done to identify allergies to pollen, mold, pet dander, dust mites and foods. In adults, the test is usually done on the forearm or on the back. 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, the nurse draws small marks on your skin and applies a drop of allergen extract next to each mark. He or she then uses a lancet to prick the extracts into the skin's surface. A new lancet is used for each allergen.

To see if your skin is reacting normally, two additional substances are scratched into your skin's surface:

• Histamine. In most people, this substance causes a skin response. If you don't react to histamine, your allergy skin test may not reveal an allergy even if you have one.
• Glycerin or saline. In most people, these substances don't cause any reaction. If you do react to glycerin or saline, you may have sensitive skin. Test results will need to be interpreted cautiously to avoid a false allergy diagnosis.

About 15 minutes after the skin pricks, the nurse observes your skin 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. The nurse will then measure the bump's size and record the results. Next, he or she will clean your skin with alcohol to remove the marks.

You may need a test that uses a needle to inject a small amount of allergen extract just into the skin on your arm (intradermal test). The injection site is examined after about 15 minutes for signs of an allergic reaction. 

Before you leave our office, you'll know the results of a skin prick test or an intradermal test. 

A positive skin test means that you may be allergic to a particular substance. Bigger wheals usually indicate a greater degree of sensitivity. A negative skin test means that you probably aren't allergic to a particular allergen.

Keep in mind, skin tests aren't always accurate. They sometimes indicate an allergy when there isn't one (false-positive), or skin testing may not trigger a reaction when you're exposed to something that you are allergic to (false-negative). You may react differently to the same test performed on different occasions. Or you may react positively to a substance during a test but not react to it in everyday life.

Your allergy treatment plan may include medications, immunotherapy, changes to your work or home environment, or dietary changes. Ask our provider to explain anything about your diagnosis or treatment that you don't understand. With test results that identify your allergens and a treatment plan to help you take control, you'll be able to reduce or eliminate allergy signs and symptoms.