A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue. Boils which are expanded are basically pus-filled nodules. Individual boils clustered together are called carbuncles. Most human infections are caused by coagulase-positive S. aureus strains, notable for the bacterias ability to produce coagulase, an enzyme that can clot blood. Almost any organ system can be infected by S. aureus. Signs and symptoms
Boils are bumpy, red, pus-filled lumps around a hair follicle that are tender, warm, and painful. They range from pea-sized to golf ball-sized. A yellow or white point at the center of the lump can be seen when the boil is ready to drain or discharge pus. In a severe infection, an individual may experience fever, swollen lymph nodes, and fatigue. A recurring boil is called chronic furunculosis. Skin infections tend to be recurrent in many patients and often spread to other family members. Systemic factors that lower resistance commonly are detectable, including: diabetes, obesity, and hematologic disorders. Boils can be caused by other skin conditions that cause the person to scratch and damage the skin.Boils may appear on the buttocks or near the anus, the back, the neck, the stomach, the chest, the arms or legs, or even in the ear canal. Boils may also appear around the eye, where they are called styes.
A boil on the gum is called intraoral dental sinus, or more commonly, a gumboil. Complications
The most common complications of boils are scarring and infection or abscess of the skin, spinal cord, brain, kidneys, or other organs. Infections may also spread to the bloodstream (bacteremia) and become life-threatening. S. aureus strains first infect the skin and its structures (for example, sebaceous glands, hair follicles) or invade damaged skin (cuts, abrasions). Sometimes the infections are relatively limited (such as a stye, boil, furuncle, or carbuncle), but other times they may spread to other skin areas (causing cellulitis, folliculitis, or impetigo). Unfortunately, these bacteria can reach the bloodstream (bacteremia) and end up in many different body sites, causing infections (wound infections, abscesses, osteomyelitis, endocarditis, pneumonia) that may severely harm or kill the infected person. S. aureus strains also produce enzymes and exotoxins that likely cause or increase the severity of certain diseases. Such diseases include food poisoning, septic shock, toxic shock syndrome, and scalded skin syndrome. Almost any organ system can be infected by S. aureus. Squeezing or cutting boils in the danger triangle of the face can be particularly dangerous if done outside a medical setting, as blood vessels in this area drain into the brain and can carry serious infections there.When a boil bursts, a seemingly solid, whitish colored pus initially appears then the pus and some blood follows. Causes
Bacteria
Naturally the cause is bacteria such as staphylococci that are present on the skin.