A carbuncle is a skin infection that often involves a group of hair follicles. The infected material forms a lump, called mass, which occurs deep in the skin.

When you have more than one carbuncle, the condition is called carbunculosis.

See also: Skin lesion

Most carbuncles are caused by the bacteria staphylococcus aureus. The infection is contagious and may spread to other areas of the body or other people.

A carbuncle is made up of several skin boils (furuncles). The infected mass is filled with fluid, pus, and dead tissue. Fluid may drain out of the carbuncle, but sometimes the mass is so deep that it cannot drain on its own.

Carbuncles may develop anywhere, but they are most common on the back and the nape of the neck. Men get carbuncles more often than women.

Because the condition is contagious, several family members may develop carbuncles at the same time. Often, the direct cause of a carbuncle cannot be determined.

Things that make carbuncle infections more likely include:

• Friction from clothing or shaving
• Poor hygiene
• Poor overall health

Persons with diabetes, dermatitis, and weakened immune systems are more likely to develop staph infections.

A carbuncle is a swollen lump or mass under the skin. It may be the size of a pea or as large as a golf ball. The carbuncle may be red and irritated and might hurt when you touch it.

It may also:

• Grow very fast
• Have a white or yellow center (pustule)
• Weep, ooze, or crust
• Spread to other skin areas

Sometimes, other symptoms may occur. These may include:

• Fatigue
• Fever
• General discomfort or sick feeling
• Skin itching before the carbuncle develops

Your doctor will look at your skin. The diagnosis is primarily based on what the skin looks like. A skin biopsy may be done to help make the diagnosis or determine the exact type of bacteria involved.