Boils

Boils can occur anywhere on your skin, but appear mainly on your face, neck, armpits, buttocks or thighs — hair-bearing areas where you're most likely to sweat or experience friction. Signs and symptoms of a boil usually include:

• A painful, red bump that starts out about the size of a pea
• Red, swollen skin around the bump
• An increase in the size of the bump over a few days as it fills with pus (can sometimes reach the size of a baseball)
• Development of a yellow-white tip that eventually ruptures and allows the pus to drain out

Carbuncles

A carbuncle is a cluster of boils that form a connected area of infection. Carbuncles often occur on the back of the neck, shoulders or thighs. Compared with single boils, carbuncles cause a deeper and more severe infection and are more likely to leave a scar. People who have a carbuncle often feel unwell in general and may experience a fever and chills.

When to see a doctor

You usually can care for a single, small boil yourself. But see your doctor if you have more than one boil at a time or if a boil:

• Occurs on your face
• Worsens rapidly or is extremely painful
• Causes a fever
• Is more than 2 inches (5 centimeters) across
• Hasn't healed in two weeks
• Recurs