Signs and symptoms
... A boil usually appears suddenly as a painful pink or red bump about 1/2 inch in diameter. The surrounding skin may also be red and swollen. Within 24 hours, the bump fills with pus. It grows larger an...

Causes
... Boils usually form when one or more hair follicles — the tube-shaped shafts from which hair grows — become infected with staph bacteria (Staphylococcus aureus). These bacteria, which norma...

Risk factors
... Although anyone — including otherwise healthy people — can develop boils or carbuncles, the following factors can increase your risk: Poor general health. Having chronic poor health makes ...

When to seek medical advice
... You usually can care for a single, small boil yourself. But see your doctor if a boil occurs on your face or spine or if you have: A boil that worsens rapidly or is extremely painful Boils that are ve...

Screening and diagnosis
... Doctors usually diagnose a boil simply by looking at your skin, but sometimes they take a sample of pus to check for the type of bacteria it contains. If you have recurring infections, you may be test...