Cause Boils are caused by certain bacteria, especially Staphylococcus aureus. White blood cells, which are part of the body's defense system, move into the area to fight the bacteria. This produces white or yellow pus, which consists of white blood cells, bacteria, and dead skin cells. Incidence Boils are very common, appearing most often on the face, neck, breasts, and buttocks. Some people who are otherwise healthy develop recurrent boils.
Carbuncles also occur in otherwise healthy people.
Males frequently develop carbuncles on the back of the neck. People with lowered resistance to infection, including those with diabetes mellitus, have an increased susceptibility to carbuncles. Symptoms you are likely to notice A boil begins as a red, tender lump. Over the period of one to two days, it fills with pus, becoming larger and more painful. Usually it continues to grow for a week or longer, until it bursts.