The range of bacterial skin infections is wide, from simple boils to a widespread and life-threatening bacterial infection that involves deeper layers of skin and has the potential to cause blood poisoning. In healthy individuals, treatment of an infection with appropriate antibiotics is generally successful. Problems can arise when a person's immune system is compromised in some way, by illnesses such as cancer or AIDS. Infection of a pre-existing wound may also be more difficult to treat, as many cases where the bacteria involved are resistant to antibiotics. The study of diseases affecting the skin is known as dermatology.
Bacterial skin infections are common, even though the skin forms such an effective barrier that people may constantly come into contact with bacteria without skin problems occurring. Any break in the skin makes it more likely for bacterial disease to establish itself, so it is important to keep cuts and scrapes clean and covered. Infectious skin diseases are also more prevalent in those people with suppressed immune systems or with conditions such as diabetes, where circulation is impaired.
The most common types of bacteria involved in bacterial skin infections are known as Staphylococcus and Streptococcus. Staphylococcal infection typically causes an abscess or boil, sometimes referred to as a furuncle. This is an uncomfortable and possibly painful red lump associated with a hair follicle. Furuncles may cluster together to form what are called carbuncles. Treatment involves hot compresses to draw out the infection and antibiotics, if necessary.
Cellulitis is a painful infection of the deeper layers of the skin, which appears as an area of redness, warmth and swelling that gradually spreads. It often occurs near a break in the skin, and the patient may be feverish. Antibiotics and pain relief are used to treat the condition and most people recover completely. A similar illness known as erysipelas, or St. Anthony's fire, affects more superficial layers of the skin, most often on the legs or face. The infected area appears extremely red with a definite, raised border and is usually treated in a similar way to cellulitis.
Impetigo is one of the bacterial skin infections which may affect healthy skin and is most commonly seen in young children. A rash usually appears several days after infection, with small blisters which burst to leave crusty, golden patches on the skin. The face is the area most frequently affected. Antibiotic cream is used to treat the condition, after gently washing away any crusts with soap and water. As impetigo is contagious, children should not go to school until antibiotic treatment has been carried out for a couple of days and there is no more evidence of blisters or crusting.