A boil, also known as a furuncle, is a painful skin infection that typically begins as a red, swollen, and tender bump.
It’s caused by a bacterial infection, most commonly Staphylococcus aureus, which enters the skin through a hair follicle or a small cut.
Over time, the bump fills with pus, grows larger, and forms a white or yellow center. Boils can develop anywhere on the body and may be accompanied by fever or chills.
They often resolve on their own but may require medical treatment, such as drainage or antibiotics in severe cases.