Allergy Patch Testing

Allergy patch testing is a dermatological procedure that determines whether a patient's skin rash is caused or aggravated by an allergy to substances that come into contact with the skin. This testing requires additional time, effort, and expertise to perform.

Performed at Kelsey-Seybold's Memorial Villages Campus, allergy patch testing is used to evaluate more than 80 contact allergens. In fact, we are one of the few facilities in the Houston area that offers comprehensive patch testing in our clinics, without our patients having to wait months for an appointment.

About the Procedure

Kelsey-Seybold Clinic uses North American Series patch tests. These allow us to test a series of over 80 allergens that are most common in North America and which are chosen specific to your particular case.

If it is determined that you may have contact dermatitis, our staff will apply tiny amounts of substances that are common allergens with small patches that adhere to your skin. The most common area of testing is the back. After 72 hours, you return to our offices where we will remove the patches and examine the test results.

You will be asked to return in another 48 hours to see if there is a delayed allergic reaction to any of the substances.

Substances Evaluated

One of the benefits of patch testing is that it can detect allergic reactions potentially due to more than 80 substances that are commonly in contact with the skin.

These substances include:

• Preservatives
• Metals
• Fragrances
• Cosmetics ingredients
• Leather chemicals
• Lanolin

It's important to note that patch testing only detects allergens that cause contact dermatitis. It does not diagnose any other types of allergies, such as food allergies.

Treatment Options

After patch testing, your allergist and their team will discuss treatment options for any allergies that have been detected. These treatments may range from simply avoiding the allergen to medications.

Treatment options to alleviate your contact dermatitis may include:

• Avoiding the substance that triggers your reaction
• Washing with soap and water after exposure to a substance
• Cold, damp compresses applied to any blistering that develops on the skin
• Oral or topical prescription corticosteroids
• Oral prescription medications
• Phototherapy

Testing "Do"s and "Don't"s

We recommend that during patch testing, you follow some simple guidelines that will help to make the testing more accurate and more comfortable for you.

Do Not:

• Get your back wet during the week of testing
• Expose your back to the sun or artificial sunlight (tanning beds) during the week of testing
• Take prescription corticosteroids for up to four weeks before or during the week of testing

Do:

• Avoid sports, heavy physical work or anything that results in sweating during the week of testing
• Wear an old bra or shirt for the week of the tests and wear a soft, non-abrasive shirt while sleeping to protect patches
• Consider wearing shirts that open at the front, rather than those that have to be pulled over your head
• Tape the edges of any patches that begin to come off during the week of testing with medical tape
• Note the date and time any patch comes completely off
• Contact your doctor if you become concerned about anything during testing
• Contact your doctor if you develop a reaction at the site of testing after testing is completed

Benefits and Risks

Patch testing is the test of choice when testing for contact allergens that cause skin reactions.

With patch testing, it's expected that the patient will experience skin reddening and itching at several testing sites. This indicates a positive result. However, there are some risks and side effects of patch testing that may include:

• Blistering at sites with positive results
• A reaction that may continue for up to a month
• Eczema at the testing sites, for those who have had eczema in the past
• An increase or decrease in the pigment of the skin where patches are placed, which may last for months or permanently
• An infection at the testing sites (rare)

Who Can Get Tested?

Patients who are most likely the best candidates for patch testing are those who have had recurrent rashes or other reactions on their skin to substances with which they regularly come into contact (also known as contact dermatitis). Patients of any age can undergo patch testing safely.

If you have unexplained dermatitis and would like more information on patch testing at Kelsey-Seybold's Memorial Villages Campus, please call our 24/7 Contact Center at 713-442-0427.