Patch testing is a common diagnostic tool used to identify the specific agent that triggers contact dermatitis, an itchy rash that can breakout on your skin in response to a substance to which you are allergic. Common trigger substances include poison ivy, jewelry, hair care products, cleaning solution, detergent, cosmetics, perfumes, and latex rubber.
Most dermatologists use the TRUE Test, which is a very good screening tool but is limited to testing 28 chemicals. At Affiliated Dermatologists we offer an extensive patch testing. We have access to 100’s of allergens which can be special ordered for you if necessary.
The patch testing procedure is simple and painless. In order to identify specific triggers, several patches will be taped onto the skin on the back containing various potential chemicals. These chemicals are then left on the skin for 48 hours, and must remain dry during this time. After 48 hours, the patch test is removed and an initial reading is taken to observe any reactions. An additional reading may be taken after another 24-48 hours. Before undergoing patch testing, patients should stop using oral and topical corticosteroids in the area to be tested, avoid oral antihistamines, and should not expose the test area to the sun for at least three weeks.
When reading the results, the doctor may classify each spot on a scale from negative (meaning no reaction) to extreme reaction (meaning positive results for substance). Strong results may cause blisters or ulcers on the skin, which can be treated once the test is complete.
Once positive results have been determined, patients can take steps to avoid their triggers and prevent contact dermatitis from occurring. We provide a comprehensive list of products a patient may use based on their individual test results and specific information on your individual triggers and how to prevent contact.