Find out about COVID-19, COVID-19 vaccines, and Mayo Clinic patient and visitor updates.
Brain tumor, breast cancer, colon cancer, congenital heart disease, heart arrhythmia. See more conditions.
Hives, also called urticaria, causes itchy welts that may be triggered by foods, medications or other substances. Changes in color of the affected area might be less visible on brown or Black skin.
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 Press.
Mayo Clinic is a nonprofit organization and proceeds from Web advertising help support our mission. Mayo Clinic does not endorse any of the third party products and services advertised.
A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.