We are open for safe in-person care.
Featured conditions Brain tumor, breast cancer, colon cancer, congenital heart disease, heart arrhythmia. See more conditions.
Featured conditions
Subscribe to Housecall
Our general interest e-newsletter keeps you up to date on a wide variety of health topics.
Patch testing can be helpful in determining if you're allergic to a specific substance. Small amounts of different substances are placed on your skin under an adhesive coating. Your doctor then checks for a skin reaction under the patches.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic.