While a single boil is a painful pus-filled lump that grows until it ruptures, a carbuncle is a cluster of such painful pus-filled boils that are connected.
A carbuncle is usually more severe than a boil and should be treated by your dermatologist. A carbuncle should never be picked or squeezed. Doing that could cause the infection to spread. A carbuncle is likely to be a more severe infection and they often leave scars. Staphylococcus, a common bacteria on the skin, is often the cause of a boil or carbuncle, and it usually enters and begins to grow into a carbuncle where the skin has been opened by a cut, bug bite, or other sensitive skin area.
Most often, carbuncles occur on the back of your neck, your shoulders, or thighs. The growth of a carbuncle can also cause you to have a fever, chills, and feel sick. If this happens, please contact your dermatologist or health care professional immediately for care.
Other reasons to seek medical care for a carbuncle include extreme pain, a carbuncle that is larger than two inches or one that appears to be growing fast, one that lasts more than two weeks, and recurring outbreaks.
Those with diabetes, acne, eczema, or any kind of compromised immune system are more at risk for carbuncles, but they can occur in otherwise healthy people as well.