The surface of the human skin is, quite literally, covered in bacteria. Since bacteria aren't visible to the naked eye, a surface that looks clean might actually contain many millions of bacteria. The bacteria residing on skin are usually harmless to humans, but sometimes they can cause health issues.
Types of Bacteria
According to Todar's Online Textbook of Bacteriology, the main types of bacteria residing on the skin include the following: Staphylococcus epidermidis, Staphylococcus aureus, Corynebacteria, Streptococcus pyogenes and Mycobacteria. Other types of bacteria may passively exist on human skin but do not typically grow and thrive in the environment.
Skin Disease
Many skin diseases can result, either primarily or secondarily, from a bacterial infection, according to the textbook Medical Microbiology. Impetigo is a disease that results in contagious skin lesions, caused either by Streptococci spp. or Staphylococcus aureus. Cellulitis is a condition in the skin that results in inflammation and itching, and is caused by Streptococcus pyogenes. Staphylococcal scalded skin syndrome is a condition, often in infants, that results from Staphylococci bacteria, causing lesions over the surface of the skin. Folliculitis is another skin disease caused primarily by the Staphylococcus bacteria. Folliculitis results in pustule formation on the skin, generally in areas with hair present. Skin tuberculosis is a more serious, albeit rare, disease that results from Mycobacterium tuberculosis infection.
At Risk
Anybody can potentially be at risk for a variety of skin infections. The most commonly affected people are the very young and elderly people who have a reduced or not-fully functioning immune system. Individuals of any age with AIDS, cancer or other serious infections are also at risk. These people have an immune system that is fighting a much bigger battle with cancer or AIDS, and this allows other infections like skin disease to sneak in the back door.
Treatment
Treatment for skin disease resulting from bacteria typically includes a course of antibiotics. For bacterial infections that cause non-deep irritation of the skin, an antibiotic cream or ointment is usually the most effective solution for treatment. Infections deep in the dermis may require an oral antibiotic to clear up the infection.
Complications
MedlinePlus notes a more serious condition, sepsis, may result from bacterial diseases of the skin. Bacterial skin disease that is a result of a serious injury, such as a burn or a wound, can enter the bloodstream in certain conditions, causing an infection of the blood, or sepsis. In sepsis, the bacteria in the bloodstream flow to other parts of the body and cause a secondary infection. Sepsis is a very serious condition that requires admittance to a hospital, where a heavy course of antibiotics and oxygen treatment is prescribed. In very serious cases where the bacteria is not put under control with antibiotics, death can occur.
