If you are suffering from allergies and cannot determine exactly what is triggering you, allergy testing can help determine what you are sensitive to. There are a few different methods to test for a variety of food and environmental allergies, and while skin pricks are still a reliable form of testing, advances in dermatology have also created a patch method for comprehensive, comfortable allergy testing. Both of these methods are reliable but are often performed for different reasons. At Rao Dermatology, we commonly perform patch testing on our patients to determine the causes allergic reactions.
When is Patch Testing Recommended?
Allergy patch testing is typically indicated when patients are experiencing contact dermatitis to see if it has caused or exacerbated by a contact allergy. Skin prick testing is used to test for hay fever-type allergies, and skin prick tests are not typically effective for patients with skin rashes.
How Patch Testing Works
There is a baseline series of substances that are applied to every patient, and our medical team will apply other substances that are appropriate for each patient depending on their unique condition. The applied substance/allergen has gone through testing to give it the right concentration to produce a slight allergic reaction in allergic patients without irritating people who aren’t allergic to it.
Some patients react to every substance with a patch test, creating a false positive result. Other people produce false negatives, showing no reaction to substances that they know they are allergic to. Multiple tests may be necessary to obtain the best results. Our medical team will provide comprehensive testing and thoroughly evaluate your results to get the most accurate reading of your patch testing.
What Can I Expect During the Testing?
During the initial appointment, a variety of patches containing small doses of allergen substances is applied to the back. This can be anywhere from 25 to 150 different substances. They are adhered with skin-safe tape and typically have to stay in place for 48 hours. When the patient returns, the patches are removed, and the positive test sites are marked with a black pen. After another 48 hours, the patient has their back inspected for marks that were visible 48 hours before. If the marks are still visible, it means the patient is most likely allergic to that substance.
While many assume that skin prick and patch testing are the same, this is not the case. Both test for allergies but each one tests for different types of allergies. Skin prick testing is typically done for patients who have possible allergies to foods, animal dander, dust mites, and pollen/mold. Patch testing is mostly used for people who have contact allergies, meaning they break out in rashes that last for an extended period after touching an allergen.
Knowing the right type of testing to look for can help streamline the process of figuring out what your specific allergies are. Contact Rao Dermatology today to schedule a consultation and determine if allergy patch testing can help you properly diagnose your skin irritations.