IN THIS TOPIC
OTHER TOPICS IN THIS CHAPTER
By
Wingfield E. Rehmus
, MD, MPH, University of British Columbia
Reviewed/Revised Jun 2023
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- Classification
- Causes
- Risk Factors
- Treatment
- Prevention
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 pre-existing 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 of Bacterial Skin Infections
Some infections involve just the skin, and others also involve the soft tissues under the skin. Relatively minor infections include
Carbuncles Skin Abscesses
Ecthyma Impetigo and Ecthyma Impetigo is a superficial skin infection that leads to the formation of scabby, yellow-crusted sores and, sometimes, small blisters filled with yellow fluid. It is caused by Staphylococcus... read more
Erythrasma Erythrasma Erythrasma is infection of the top layers of the skin caused by the bacterium Corynebacterium minutissimum. (See also Overview of Bacterial Skin Infections.) Erythrasma affects mostly... read more
Folliculitis Folliculitis and Skin Abscesses Folliculitis and skin abscesses are pus-filled pockets in the skin resulting from bacterial infection. They may be superficial or deep, affecting just hair follicles or deeper structures within... read more
Furuncles Folliculitis and Skin Abscesses Folliculitis and skin abscesses are pus-filled pockets in the skin resulting from bacterial infection. They may be superficial or deep, affecting just hair follicles or deeper structures within... read more
Impetigo Impetigo and Ecthyma Impetigo is a superficial skin infection that leads to the formation of scabby, yellow-crusted sores and, sometimes, small blisters filled with yellow fluid. It is caused by Staphylococcus... read more
Lymphadenitis Lymphadenitis Lymphadenitis is infection of one or more lymph nodes, which usually become swollen and tender. (See also Overview of Bacterial Skin Infections.) Lymph is a fluid that oozes out of the body's... read more
Small skin abscesses Skin Abscesses Folliculitis and skin abscesses are pus-filled pockets in the skin resulting from bacterial infection. They may be superficial or deep, affecting just hair follicles or deeper structures within... read more (pus-filled pockets in the skin)
More serious bacterial skin and skin structure infections include
Cellulitis Cellulitis Cellulitis is a spreading bacterial infection of the skin and the tissues immediately beneath the skin. This infection is most often caused by streptococci or staphylococci. Redness, pain, and... read more
Erysipelas Erysipelas Erysipelas is a superficial form of skin infection ( cellulitis) typically caused by streptococci. (See also Overview of Bacterial Skin Infections.) Erysipelas is most commonly caused by Streptococcus... read more
Large skin abscesses Folliculitis and Skin Abscesses Folliculitis and skin abscesses are pus-filled pockets in the skin resulting from bacterial infection. They may be superficial or deep, affecting just hair follicles or deeper structures within... read more
Lymphangitis Lymphangitis Lymphangitis is infection of one or more lymphatic vessels, usually caused by streptococci. (See also Overview of Bacterial Skin Infections.) Lymph is a fluid that oozes out of the body's tiniest... read more
Necrotizing skin infections Necrotizing Skin Infections Necrotizing skin infections, including necrotizing cellulitis and necrotizing fasciitis, are severe forms of cellulitis. These infections cause infected skin and tissues to die (necrosis). The... read more
Wound infections
Staphylococcal scalded skin syndrome Staphylococcal Scalded Skin Syndrome Staphylococcal scalded skin syndrome is a complication of a staphylococcal skin infection in which the skin blisters and peels off as though burned. In addition to the blistered, peeling skin... read more , scarlet fever 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 , and toxic shock syndrome Toxic Shock Syndrome Toxic shock syndrome is a group of rapidly progressive and severe symptoms that include fever, rash, dangerously low blood pressure, and failure of several organs. It is caused by toxins produced... read more are skin-related consequences of bacterial infections.
Causes of Bacterial Skin Infections
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 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 ) 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 for 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 medications 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.
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.
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 keep bacteria out. 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.
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