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Overview of Bacterial Skin Infections


Wingfield E. Rehmus

, MD, MPH, University of British Columbia

Full review/revision Apr 2021 | Modified Sep 2022

The skin provides a remarkably good barrier against bacterial infections. Although many bacteria come in contact with or reside on the skin, they are normally unable to establish an infection. When bacterial skin infections do occur, they can range in size from a tiny spot to the entire body surface. They can range in seriousness as well, from harmless to life threatening.

Bacterial skin infections develop when bacteria enter through hair follicles or through small breaks in the skin that result from scrapes, punctures, surgery, burns, sunburn, animal or insect bites, wounds, and preexisting skin disorders. People can develop bacterial skin infections after participating in a variety of activities, for example, gardening in contaminated soil or swimming in a contaminated pond, lake, or ocean.

Classification and Causes

Some infections involve just the skin, and others also involve the soft tissues under the skin. Relatively minor infections include

More serious bacterial skin and skin structure infections include

Many types of bacteria can infect the skin. The most common are Staphylococcus Staphylococcus aureus Infections Staphylococcus aureus is the most dangerous of all of the many common staphylococcal bacteria. These gram-positive, sphere-shaped (coccal) bacteria (see figure ) often cause skin infections... read more <i >Staphylococcus aureus</i> Infections and Streptococcus Streptococcal Infections Streptococcal infections are caused by any one of several species of Streptococcus. These gram-positive, sphere-shaped (coccal) bacteria (see figure ) cause many disorders, including... read more . Methicillin-resistant Staphylococcus aureus (also known as MRSA Methicillin-resistant Staphylococcus aureus (MRSA) Staphylococcus aureus is the most dangerous of all of the many common staphylococcal bacteria. These gram-positive, sphere-shaped (coccal) bacteria (see figure ) often cause skin infections... read more Methicillin-resistant <i > Staphylococcus aureus </i> (MRSA) ) is a common bacteria causing skin infections in the United States. MRSA is resistant to many commonly used antibiotics because it has undergone genetic changes that allow it to survive despite exposure to some antibiotics. Because MRSA is resistant to several antibiotics Antibiotic resistance Bacteria are microscopic, single-celled organisms. They are among the earliest known life forms on earth. There are thousands of different kinds of bacteria, and they live in every conceivable... read more that used to kill it, doctors tailor their treatment based on how often MRSA is found in the local area and whether or not it has been found to be resistant to commonly used antibiotics.

Risk Factors of Bacterial Skin Infections

Some people are at particular risk of developing skin infections:

  • People with diabetes, who are likely to have poor blood flow (especially to the hands and feet), have a high level of sugar (glucose) in their blood, which decreases their ability to fight infections

  • People who are hospitalized or living in a nursing home

  • People who are older

  • People who have human immunodeficiency virus (HIV), AIDS or other immune disorders, or hepatitis

  • People who are undergoing chemotherapy or treatment with other drugs that suppress the immune system

Skin that is inflamed or damaged is more likely to become infected. In fact, any break in the skin predisposes a person to infection.

Prevention of Bacterial Skin Infections

  • Cleaning skin with soap and water

Preventing bacterial skin infections involves keeping the skin undamaged and clean. When the skin is cut or scraped, the injury should be washed with soap and water and covered with a sterile bandage.

Petrolatum may be applied to open areas to keep the tissue moist and to try to prevent bacterial invasion. Doctors recommend that people do not use antibiotic ointments (prescription or nonprescription) on uninfected minor wounds because of the risk of developing an allergy to the antibiotic.

Treatment of Bacterial Skin Infections

  • Antibiotics

  • Drainage of abscesses

An antibiotic ointment is used if a minor skin infection develops. Antibiotics also need to be taken by mouth or given by injection if a large area of skin is infected.

Abscesses should be cut open by a doctor and allowed to drain, and any dead tissue must be surgically removed.

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