Some people develop rashes because they are allergic to certain chemicals they come into contact with in their everyday life. This is called allergic contact dermatitis. People can be allergic to a variety of chemicals, additives, fragrances, and preservatives found in everyday products. Even if a patient has been using the same products for years, allergic contact dermatitis can still occur. This is often due to manufacturers changing a product’s ingredients without the patient being aware of the change or because the patient developed an allergy that (s)he did not have in the past.
Trying to determine what substance a patient is allergic to can be an involved process, both for the patient and for the doctor. Fortunately, Drs. Martin and Bentley offer patients the option for patch testing when an allergic contact dermatitis is suspected.
As members of the American Contact Dermatitis Society, Drs. Martin and Bentley are skilled in patch testing patients for contact dermatitis. Patch testing is performed by applying strips of tape to your skin, usually on your back. These tape strips have suspected allergens (chemicals to which a patient may be allergic) embedded in them. These tape strips are usually applied on a Tuesday morning and must remain in place and dry for at least 48 hours. They will be removed on Thursday. An initial reading of your results is done on Thursday, with a final reading on the following Monday. Therefore, patch testing requires three office visits, one each on Tuesday, Thursday, and Monday. We will make ink marks on your skin during the testing. Be certain not to wash them off as they serve as a landmark to note where the different allergens were placed. You may want to wear a dark shirt as the dark ink sometimes may come off on undergarments. It is very important that the patch test areas remain dry from Tuesday until the following Monday morning.
A positive patch test shows a round, red spot or bump. Sometimes, blisters can develop. Patients may have multiple positive tests, or no positive tests. Some of the allergens are dyes, so there may be temporary staining of the skin. Patch testing is painless, but positive test results can cause some minor, temporary discomfort, usually due to itching. Sometimes a late reaction occurs about a week after patch testing. If you think you see a new positive reaction after your final result reading, please call our office for an evaluation.
Once we know what a patient’s allergies are, we are able to search the Contact Allergen Management Program. This will provide our patients with a personalized list of products that do not contain the chemical(s) that cause that patient’s allergies and thus are safe to use. Once the patient is able to identify his/her allergies, then strict avoidance of those products will usually allow patients to clear their rashes and avoid future bouts with contact dermatitis. It is critical that patients only use the products known to be safe for them in order for a contact dermatitis to clear. Complete resolution of the rash may take 4-6 weeks.
To get the best results from patch testing, we ask our patients to follow these guidelines:
- Do not take any type of steroid shot for one month prior to testing. Typical names of steroid shots include Kenalog, Solumedrol, Celestone, and Depo-Medrol
- Do not take more than 10 mg of Prednisone per day. If you are on Prednisone, do not stop it without discussing this with your doctor.
- Do not get the testing area wet. You will need to take sponge baths until after the final reading.
- Do not sweat during the testing period. Sweat will loosen the test panels and can cause ink to run, which will lead to inaccurate results.
- Avoid scratching or picking at the tape panels as they may loosen, leading to inaccurate results.
- If an area of tape becomes loose, reinforce with adhesive tape and be sure to tell us if that occurs.
- Do not remove the ink marks on your back unless instructed to do so.
If you need to cancel your patch testing appointment, please call us at 205.682.8022 as soon as possible. Patch testing requires 3 visits and you will see your doctor on all three visits. If your insurance requires a co-payment, you will have three co-payments during the week of your testing. These are payable at the time of service.
All insurance plans are different and you may want to check with your insurance company prior to patch testing to ensure that your testing will be covered to your satisfaction. Please let us know if you would like the insurance codes for this test.