A boil, also known as a furuncle, is a swollen, pus-filled growth on the skin that occurs when bacteria—even those normally found on your body—infect a group of hair follicles. Boils commonly develop ...

A gum boil is a type of periodontal disease that involves the formation of an abscess on the gums. It causes pain and swelling. If left untreated, it can spread to the teeth and surrounding tissues.

Mark Gurarie is a writer covering health topics, technology, music, books, and culture. He also teaches health science and research writing at George Washington University's School of Medical and ...