Allergic contact dermatitis is a common skin condition in which patients have become sensitized to a particular allergen or chemical in their environment and suffer from a persistent itchy rash, usually localized to the area in which the patient is exposed to the allergen. It can be extremely difficult to isolate the problem, since in many cases, patients may have been using the problem product for years without issues.
People can become “allergic” to a chemical or product that they previously never had a problem with before. Biltmore Dermatology offers comprehensive patch testing to help you determine the cause of a persistent rash or irritation.
Patch (Skin Allergy) Testing
Through history and physical examination of the patient, Biltmore Dermatology can find clues to what are the allergens which may be causing the rash. However, in many cases, your provider may need to perform tests, such as patch tests to really identify the problem clearly. Patch tests are a safe and easy way to diagnose contact allergies.
Patch tests are different from injection or scratch skin tests because they test for different allergens. In patch tests, small amounts of the possible common allergens are applied to the skin on panels and secured with tape if necessary. A positive allergy test shows up as a small red spot at the site of the patch.
Common allergens include nickel, rubber, neomycin, dyes, preservatives, medications, fragrances, poison ivy, poison oak, and related plants.
Patch Test Results
Patch testing is a one week process. Typically, the patient has to have 3 visits during a one week period. The first visit is to apply the patches. The second visit is to remove the patches and do the first interpretation. The third visit is to do the final interpretation of the results and to discuss the treatment plan moving forward.
The reason it takes one week to perform the test is that contact dermatitis is a delayed type hypersensitivity reaction. It typically takes 5-7 days for patients to develop a rash after being exposed to a product. This is why it is difficult for patients to figure it out on their own without patch testing.
Patch Test Results and Pain
Patch tests have little or no pain. However, positive reactions may cause itching and red bumps which look and feel like insect bites. The bumps and itching resolve generally quickly.
Insurance Coverage for Patch Testing
It is covered by most insurances, though it may require a prior authorization.