The most common cause for boils is staphylococcal bacteria, a germ that slips through a cut in the skin or goes down a hair to infect the follicle, according to WebMD. Boils most frequently appear on the buttocks, face, neck, shoulder and armpit. An eyelid boil is called a sty.
Soon after the infection takes root, the skin reddens, and a lump starts to grow. The lump turns white after about a week as pus gathers beneath the skin. If several boils form together, this is a more serious sort of infection known as a carbuncle, notes WebMD.
If a boil or carbuncle is surrounded by warm, swollen, red skin, the infection has become more severe. Fever often develops, and the lymph nodes occasionally swell, depending on the reach of the infection. It's time to seek medical attention when the patient runs a fever, has observable swelling in the lymph nodes, or red streaks appear on the skin near the boils. If the boil fails to drain, the pain becomes unbearable, or multiple boils appear, consulting a doctor is a good idea as well, reports WebMD.
Most people do not need emergency medical care for boils. However, people with poor health or who suffer from an immune system deficiency, diabetes or heart murmur should get medical attention for boils. If chills and high fever develop in boil patients who are already in poor health, it's time to go to the emergency room, as stated by WebMD.