Allergy Testing Specialist


Dermatologists located in Arlington, VA

Allergy Testing Q & A

Allergy Patch Testing - How to Prepare and What to Expect

Patch Testing can be used to determine if your skin condition is caused by a contact allergic reaction to some specific substances. This will involve several visits to the clinic.

  • During the evaluation, an investigation of possible causes for your symptoms will be implemented, so that an assessment can be made of which substances should be patch tested.
  • At the next visit, a so-called base line series will be tested and possible some additional series depending on the exposure that occurs in your daily environment or at your workplace. You will have the test chambers filled with various substances that can cause contact allergy taped to your back for 2 days.

Multiple patch testes applied on the back.

You must be evaluated first by a provider at SkinDC or another dermatologist to determine if patch testing is recommended for you. If a dermatologist has recommended patch testing for you, you can skip setting up an appointment for an evaluation and set up a patch testing series.

Scheduling for patch testing is very specific and unfortunately not flexible. If you schedule for patch testing you will need to commit to these appointments so we are able to read the tests accurately.

Stop taking steroids and antihistamines 1 week prior to testing.
You CANNOT wash your back or get it wet until after the second reading on Friday.

1st appointment - Tuesday
-Several pieces of tape will be applied to your back that will be removed at your Thursday appointment

2nd appointment - Thursday
-Remove tape / 1st reading

3rd appointment - Friday
Photo appointment for delayed reactions - OK to shower today after reading

4th appointment - Tuesday
-Discuss results and provide lists of products to avoid and safe products to use


Questions and answers about contact allergies and patch testing

What is contact dermatitis?

A construction worker's hands after the person has become allergic to a substance in work gloves.

Contact allergy is an allergy caused by direct contact with an allergenic substance. There are so-called cell-mediated immunity, also called Type 4 allergies (delayed hypersensitivity). The hapten (allergen) that trigger symptoms are often simple chemicals. The most common disease caused by contact allergy is contact allergic dermatitis. The most common specific the contact allergy is nickel allergy, but today there are thousands of known substances that can cause contact allergy. Other common causes of allergic contact dermatitis are substances in cosmetics, fragrances, preservatives, certain drugs for topical use, hair dye, hygiene products and chemical products. Contact allergy can not be cured, but is something you will have to learn to live with.

What is a patch test and how will it look like?

A number of patch tests with different substances will be taped on your back (the number depends on the physician's choice). Each patch test accommodates 10 potential allergic substances. A base line series with the most common allergy-causing substances is usually always tested. Additional substances can be added depending on what you and your doctor has come up with before.

For how long do I have these patch tests on me?

The patch tests will be removed after about 2 days, and a first reading can be made 20-30 minutes after removal, if test patches are removed at the clinic. If you remove the test patches at home, then will the reading take place three days after test application. Do not remove the tests before the time your doctor has recommended you. If you get a very strong reaction with strong itching and redness in any of the test patches, contact your doctor, who may then decide whether you should stop and remove the patch test. Your doctor will inform you if further readings are required within the next 5 to 7 days.

What should I consider during text time?

Keep the test area on the back dry during this time period and avoid heavy and physical exercises that can cause excessive sweating as this may lead to that the patch tests come off. Cortisone creams and antihistamines should not be used during the entire test period. Avoid sunbathing on the test area. The recommendation is also that you should wear loos clothing and sleep in a t-shirt as this helps to prevent the patch tests from rubbing off or peeling off the skin.

The patch test is getting loose, what should I do?

Have someone press on the test patches. If necessary, you can also reinforce them with additional tape on the edges of the test units.

What should I do if the itch during the patch test?

Try not to scratch at the test site, because the itching is usually a sign of a positive reaction and the itching can alter the test results.

How do I know if I have a contact allergy?

Examples of how various degrees of contact allergic reactions may look following a patch test.

On your first reading, the doctor will carefully examine the test area for signs of an allergic reaction. It may look like a small rash with swelling, redness and / or small blisters. This can be difficult to decipher at first reading, and your doctor will advise you if additional readings are required over the coming days.

What is the benefits from knowing what I'm allergic to?

Your doctor will tell you what you are allergic to. Where and in what types of products the substance can be found and how you do to avoid the substance in the future. You will also get an information sheet where some of this information stands.

It turned out that I was not allergic to any of the tested substances, what do I do now?

Negative results are very common. If the test is negative, this is also important information, you will not need to avoid the topics you now tested. But there are many more substances that can cause your symptoms. Some patients need to do further testing to determine if they are allergic to these substances. Your doctor can also determine whether your symptoms are due to an irritation reaction, and thus tell you about how to better take care of your skin and avoid irritating substances. If your doctor determines that your skin reaction is due to anything other than a contact allergy, you may be referred to a specialist for further tests and treatment.



Please check with your insurance company for any estimated out-of-pocket cost. Without coverage or if you have a high deductible, the cost can reach up to $850.

Below is the information you will need to provide to your insurance carrier to determine if you are covered before coming for treatment.

Procedure Name: Allergy Testing
Procedure code (CPT): 95044
# of units: 80