Skin boils are pockets of infection, or abscesses, within the deep skin layers. The bacterium Staphylococcus aureus causes most boils, although other species of bacteria can also cause these painful skin lesions. Boils, also known as furuncles and carbuncles, develop when bacteria breach the natural skin barrier and invade the tissue, often through a hair follicle. Furuncles are individual pockets of infection; carbuncles represent the merger of multiple skin abscesses. Treatment depends on the number and severity of the boils.
Cuts and Scratches
Millions of bacteria inhabit the skin surface. A minor cut or scratch provides bacteria an opportunity to invade the skin, potentially leading to the development of a boil, notes the website MayoClinic.com. At the site of the injury, bacterial invasion triggers a rigorous immune system response. Large numbers of white blood cells migrate to the infection site to defend the body against the invading bacteria. In the ensuing battle between the multiplying bacteria and the white blood cells, a boil develops -- an inflamed pocket of pus, bacteria and tissue debris. In most cases, a boil eventually ruptures spontaneously, and the contained debris drains. Once the material in the abscess drains, the skin lesion heals.
Skin Friction
Repetitive friction or rubbing of the skin may cause microscopic breaks in the surface barrier, providing an opportunity for bacterial invasion and the development of a boil. Tight-fitting underclothing or pants often cause skin friction involving the buttocks, groin and inner thighs -- common sites for boils. A skin abscess over the tailbone represents a specific type of boil known as a pilonidal abscess. Skin friction in this region may contribute to the formation of boils. Pilonidal abscesses tend to recur and may eventually require surgery if other forms of therapy fail to control the condition, reports the website of Baptist Health Systems.
Poor Hygiene
Poor hygiene may increase the likelihood of boil formation, advises Mount Sinai Medical Center. In the absence of regular bathing or showering, dead skin cells, dirt and bacteria accumulate on the skin surface. The abundant bacteria may overwhelm the body's defenses and invade through a hair follicle, leading to the development of a boil. The most common sites for boils include the groin, underarms, buttocks, thighs, neck and face.
Atopic Dermatitis
Atopic dermatitis is a chronic form of eczema, characterized by itchy patches of inflamed skin. Patients with atopic dermatitis have a defective skin barrier, which increases the likelihood of bacterial invasion, reports the New Zealand Dermatological Society on the medical information website DermNet NZ. People with atopic dermatitis frequently develop boils due to skin barrier defects, lack of protective skin oils and small skin abrasions caused by repetitive scratching.
