[header] How to patch test skin [title] Understand the basics. [step] Patch tests are used to test how allergic you are when you come into contact with certain substances. Patch tests are different from prick or scratch tests.
[substeps] A scratch test checks for reactions to common allergens that may give you symptoms from hives to a runny nose. The nurse scratches or pricks the skin to get the allergen under the skin.