A boil is a painful, pus-filled bump that forms under your skin when bacteria infect and inflame one or more of your hair follicles. A carbuncle is a cluster of boils that form a connected area of infection under the skin.

What is a boil? The bacteria that cause boils are contagious, and skin infections can be spread from contact with the fluid. A boil is a localized infection in the skin that begins as a reddened, tender area. Over time, the area becomes firm, hard, and increasingly tender.

A boil is a skin infection that is usually caused by the bacteria Staphylococcus aureus (staph). A carbuncle is a group of boils located in one area of the body.

To help a boil heal, apply a warm, moist compress for 10 minutes, three times a day. If a boil lasts over a week, you should see a healthcare provider. A furuncle, commonly known as a boil, starts as a small, painful bump on the skin, often due to a bacterial infection.

Boils are usually caused by a bacteria called Staphylococcus (staph). Some staph infections develop into abscesses and can become serious very quickly. This germ can be present on normal skin and enters the body through tiny breaks in the skin or by traveling down a hair to the follicle.

A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue. [1]