Skin Patch Testing

About Patch Testing:

What is allergic contact dermatitis?

Allergic contact dermatitis is a rash caused by direct contact with an allergenic substance. The chemicals that cause this rash are referred to as allergens and can be an ingredient in your makeup, hair dye, fragrances, jewelry, topical medications, clothing, cleaning supplies, gloves, paint, shoes, etc. Even small amounts of allergen can provoke allergic contact dermatitis in sensitive individuals. Allergic contact dermatitis cannot be cured, but it can be controlled adequately if the culprit allergen is avoided.

What is the benefit of doing a patch test?

Patch testing is reliable, safe, and easy. It can help to determine if your rash is caused by a reaction to specific chemicals. Identifying potential allergens and knowing which products to avoid will greatly improve your rash, although it may take several weeks. If you have a positive test, we will teach you how to avoid your allergen and offer a list of “safe” products to use.

How does the patch test work?

It’s easy! On day 1 (Monday), three patches will be applied to your upper back. These patches contain 36 of the most common allergens. No needles are involved. On day 3 (Wednesday), you will return to the office to have the patches removed. The skin will be marked and examined for any preliminary reactions. On day 5 (Friday), the skin is examined again for a delayed reaction, and tests results are reviewed with you.

What does a positive reaction look like?

The doctor will review your results when the patches are removed. Positive reactions range from mild redness with a little swelling to bright red, blistered skin.

What happens if I am not allergic to any of the tested substances?

Negative results are common (~25%). Patch testing helps to narrow the potential allergens that are causing your reaction. If the test is negative, this is also important information as it tells us that you need not avoid the tested substances. Please note that patch testing does not always explain the cause of a rash and does not include environmental or food allergy testing.

Will insurance cover my test?

We will contact your insurance and confirm approval prior to scheduling your appointment. Most insurance plans cover patch testing to a great extent, but you may incur some personal charges. Copays are collected at the time of service. Any deductibles that have not been met may also require additional payment.

What are the disadvantages of patch testing?

There are three visits in one week. You cannot let water touch your back from Monday to Friday. The test area can become very itchy, although this is a good sign as it usually indicates a positive finding.

Where can I learn more about contact dermatitis?

The Contact Dermatitis Institute is an excellent resource for patients and has information sheets on the most common allergens –

During Patch Testing:

What do I need to know before my patch test?

• Keep your back dry for the entire test period – no showering, heavy exercising, or excessive sweating. Moisture on the back will cause the allergens to run together and/or the patch tests to come off, negating the validity of the test. Sponge bathing and washing your hair in the sink is okay.

• Do not take oral steroids or use topical steroids on the back for at least two weeks.

• Wear loose clothing during the test period.

• Do not apply any fragrances or creams on your skin on the day of the test.

• Avoid excessive sun exposure to the back for 1-2 weeks prior to test and during the test period.

• Itching and burning are common – but DO NOT SCRATCH.

• A flare up of your skin rash may occur during the test period.

What should I do if my skin itches or burns during the patch test?

Itching and burning are common side effects. Try not to scratch at the test sites, because itching is usually a sign of a positive reaction and scratching the affected site can alter the results. If you get a very strong reaction with intense itching, burning, redness or pain, contact the office immediately.

The patches are getting loose. What should I do?

Have someone press on the test patches. You can also reinforce them with additional hypoallergenic tape on the edges of the panels. Panels that are removed or damaged will require a complete retest so avoid any unnecessary manipulation of the patches as well as any movements that could cause the patches to detach.

After Patch Testing:

I tested positive for an allergen. Now what?

Refer to the allergen forms given to you by our staff. The allergen forms will contain list a of the most commonly used products which contain that specific allergen. You must try your best to avoid all products containing the allergen. Check the ingredients of products that you are currently using and ensure that they do not contain the positive allergen.

I am avoiding all the allergens that I tested positive to, but my rash has not cleared up? Am I doing something wrong?

It can take up to two months of allergen avoidance for your rash to visibly improve. Be patient and hang in there! If your rash persists past this time, be sure that you are familiar with all of the alternative names for your list of allergens. Sometimes the ingredients on the bottle may have a synonym for the allergen and you may not realize.

Contact Us

If you would like to call us directly our phone number is +1 (660) 627-7546 or you can use the form below.


Please do not submit any Protected Health Information (PHI).


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