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Intradermal Skin Testing


Intradermal Skin Testing Questions and Answers

Believe you might have an allergy? Not sure what’s causing your reaction? Allergy and Asthma Clinic of Maryland provides in-depth allergy testing. For more information, please call us or book an appointment online. We serve patients from Silver Spring MD, Ammendale MD, Takoma Park MD, College Park MD, Langley Park MD, and Rockville MD.

Intradermal skin testing is a standard allergy test. The procedure involves injecting a small amount of an allergen beneath the surface of the skin. When a reaction occurs, an allergy is determined. These tests have helped in the determination of millions of allergies.

What is intradermal skin testing?

Intradermal allergy tests analyze the way your skin reacts to different allergens and identifies what is causing your reactions. A small amount of the suspected allergen or allergens is injected beneath the skin’s surface and then observed for any signs of an allergic reaction. It will take about 10 to 15 minutes for a reaction to occur. As it pierces deeper into the skin, intradermal testing is more sensitive and provides more accurate results than that of skin prick tests.

It is extremely important that these tests be administered by an allergy technician as this will ensure your safety and avoid any unnecessary complications.

How do you perform a skin test?

Intradermal skin tests are performed by creating a solution of the suspected allergens and injecting them just underneath the skin with the use of a small needle.

Typically, the allergist will inject the upper arm or forearm with a specific allergen that the patient may be allergic to.

Positive reactions on the skin testing are typically a red, itchy area with a raised center that may look similar to a mosquito bite. To help gauge the intensity of the reaction, skin testing on the arm is compared with negative (saline) and positive (histamine) controls.

It should be performed on the inner area of the forearm avoiding the flexures and the wrist areas. Skin prick testing may more easily be performed on the child’s back when under the age of three years. The procedure must be explained to the patient. The skin must be clean and free of any creams or lotions. The arm may be marked with a pen for the allergens to be tested. A drop of the allergen solution is injected into each area. A fresh needle is used for each allergen. The test site will be cleaned before receiving the injection. To prevent cross contamination, it is important not to wipe down the arm.

It is a safe and effective procedure and results are seen within 15 minutes, after which the results can be determined.

Does Intradermal allergy testing hurt?

As an intradermal skin test uses needles, a slight discomfort may be experienced, however no or very little pain should be present. If there is a positive reaction, the skin will be red and itchy. With the use of cortisone cream, this should clear up. In the rare chance that a severe allergic reaction occurs, you will be in the safety of an office under professional medical supervision.

Are intradermal skin tests accurate?

Intradermal skin tests are among the most accurate allergy tests available. As the allergen is injected beneath the skin, it allows for a deeper penetration. If you test negative for a skin prick test (SPT), you may be recommended to take an intradermal skin test, as these offer more accurate results.

If you or someone you know suspects they have an allergy or does not know what is causing their reaction, come to Allergy & Asthma of Maryland today! Our team of allergists can help you determine your allergies, so you can live a great quality of life! To get in touch with an expert, contact our office today. To schedule an appointment


Allergy & Asthma Clinic of Maryland
8630 Fenton Street, Suite 522
Silver Spring, MD 20910
Phone: 240-332-8010
Fax: 240-847-7061

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