Patch testing helps to confirm a diagnosis of an allergic contact dermatitis, which is a type of skin rash that occurs when certain substances come in contact with the skin. Examples of these substances are fragrance in perfume, adhesives used in bandages, metals found in jewelry, and glues used in shoes, just to name a few.
Anyone can develop skin irritation (also called an irritant contact dermatitis) when exposed to harsh chemicals like strong detergents, household cleansers, solvents, and acids. However, not everyone will develop an allergic contact dermatitis when exposed to allergens. Allergic contact dermatitis can only occur after the immune system in the skin learns to recognize the allergen and become activated to cause inflammation.
How is it done?
Strips of tape containing small quantities of common allergens will be applied to the skin of your back during your first visit. The allergens must remain in place and be kept dry for 48 hours.
After the 48 hours, the patches will be removed and an initial reading will be performed. The sites will be outlined with a marker, and you will be asked to return for a final reading on another day. A positive test will show a red, raised area of skin, often with itching. A strong reaction could cause blistering and, very rarely, a prolonged reaction.
Does and Dont's
Keep the skin of your back dry until the patches are removed 48 hours after applied. Until then, no showering, bathing (except for sponge baths), or swimming.
Avoid any activity that may cause you to sweat heavily (examples: exercising, shoveling). Excessive perspiration could cause the patches to fall off
If any of the patches begins to peel loose, reinforce it with adhesive tape.
Do not remove/wash the magic marker markings on your back until instructed to do so. Some of the ink sometimes does come off on clothing, so it may be a good idea to wear a