Boils and Carbuncles

What Is It?

Boils and carbuncles are localized skin infections usually caused by Staphylococcus aureus bacteria (staph). These staph infections form pockets of pus in the skin that are filled with bacteria, dead skin cells and infection-fighting white blood cells. Whether the pocket of pus is called a boil or a carbuncle depends on the location and size of the skin infection:

• A boil, also called a furuncle, begins as a painful infection of a single hair follicle. Boils can grow to be larger than a golf ball, and they commonly occur on the buttocks, face, neck, armpits and groin.
• A carbuncle is a deeper skin infection that involves a group of infected hair follicles in one skin location. Carbuncles often are found on the back of the neck, shoulders, hips and thighs, and they are especially common in middle-aged or elderly men. People with diabetes are more likely to develop carbuncles.

Symptoms

A boil looks like a red, swollen, painful bump under the skin. As the infection progresses, a whitish tip, also called a point or head, can appear at the center of the boil. This tip is usually the area where the boil's pus will drain. A carbuncle looks like a cluster of interconnected boils.

Whenever you have a boil or a carbuncle, you also can have a fever and feel generally sick. A fever is more likely with a carbuncle than with a single boil.

Diagnosis

Your doctor can diagnose a boil or carbuncle by examining your skin. If you have frequent recurrences of boils within a short period of time, your doctor may do blood tests to check for diabetes or other medical conditions that can increase your risk of repeated infections.

Expected Duration

In many otherwise healthy patients, a small boil will form a white tip (come to a head) and drain within five to seven days. However, carbuncles or very large boils can last longer and may not drain on their own. These may require antibiotics and drainage by a physician.

Prevention

If you have an area of skin that is prone to boils or carbuncles, keep the area clean and dry, and avoid wearing tight clothing that doesn't allow the skin to breathe. Washing daily with an antibacterial soap also can help. At the earliest sign of irritation or a bump at a hair follicle, use warm compresses to open up the blocked pore and drain any early infection. If you develop signs of inflammation or infection at a hair follicle (folliculitis) as a result of shaving, you should avoid shaving in that area to prevent bacteria from being spread from this area to other parts of the skin.