boil, or skin abscess, is a localized infection deep in the skin. A boil generally starts as a reddened, tender area. Over time, the area becomes firm and hard. Eventually, the center of the abscess softens and becomes filled with white cells that the body sends to fight the infection. This collection of white cells is known as pus. Finally, the pus "forms a head" and drains out through the skin. Skin abscesses may occur anywhere on the body. They affect people of all ages.

There are several different types of boils. Among these are:
Furuncle or carbuncle : This is an abscess in the skin caused by the bacteria Staphylococcus Aureus. It can have one or more openings onto the skin and may be associated with a fever or chills.

Cystic acne : This is a type of abscess formed when oil ducts become clogged and infected. Cystic acne is most common in the teenage years.

Hidradenitis suppurativa : This is an illness in which there are multiple abscesses that form under the arm pits and in the groin area. These are a result of local inflammation of the sweat glands.

Pilonidal cyst : This is a special kind of abscess that occurs in the crease of the buttocks. These frequently form after long trips that involve sitting.

Skin lesion maybe seen.

Abscess will be in the form of open sore or closed, domed nodule.

There maybe localized swelling, redness and induration.

Affected area is tender and warm to touch.

Complications of abscess are :

Localized spread of infection.

Impingement on the functioning of adjacent structures.

Gangrene (tissue death).

Systemic spread of infection will cause :

Endocarditis.

Osteomyelitis.

Multiple new abscesses ("seeding" of infection).

Abscess formation on the joints, pleura, or other locations.

Abscess - Medical term for a common boil, a collection of pus beneath the skin.

Carbuncle - Painful localized bacterial infection. A circumscribed inflammation of the skin and deeper tissues that terminates in a slough and suppuration and is characterized by a painful node, at first covered by tight reddened skin which later becomes thin and perforates, discharging pus through several openings.

Furuncle - An acute circumscribed inflammation of the subcutaneous layers of the skin, gland or hair follicle.

Cyst - A closed sac or capsule, usually filled with fluid or semisolid material.

Antibiotic - A substance that inhibits the growth of or destroys bacteria or other microorganisms.

Pus - A thick whitish-yellow fluid which results from the accumulation of white blood cells (WBCs), liquified tissue and cellular debris. Pus is commonly a site of infection or foreign material in the body.

Gangrene - A necrosis, or death of tissue, usually due to deficient or absent blood supply.

Osteomyelitis - Inflammation of the bone due to infection, by the bacteria salmonella or staphylococcus.

Pleura - The thin covering that protects and cushions the lungs. The pleura is made up of two layers of tissue that are separated by a small amount of fluid.