UNDERSTANDING
BACTERIAL SKIN INFECTIONS
Understanding bacterial skin infections
What is a skin infection?
The skin is the body’s largest organ, that protects the body from germs, regulates body temperature and helps with sensations like feeling hot and cold. When the skin is wounded in any way, or you have a poor blood supply to an area of your body or if your immune system is weak, you can become susceptible to infections. Infections can be caused by bacteria, viruses, fungi, or parasites. Some infections are common; some uncommon. Some infections cover a small area on the surface of your skin, while others spread to a larger area and can go deep into the skin.
Bacterial skin infections
Bacterial skin infections are caused by bacteria; the most common ones being Staphylococcus aureus (“Staph”) and Streptococcus pyogenes (“Strep”).
Minor bacterial infections – also known as skin and soft tissue infections (SSTIs) – include:
- Impetigo is very contagious skin infection that mostly affects children, particularly during humid summer months. A dominant form of the disease is a non-bullous type that presents with one sore (erosion) or a cluster on exposed skin areas. Impetigo first appears in the form of small blisters formed in or beneath the skin (vesicles) or pimples filled with pus (pustules) that rupture and form a honey-yellow crust around the area.
- Bacterial folliculitis is an infection of the hair follicles, which is caused when follicles are blocked by ingrown hairs, oils, or skin care products (chemical irritation), trapping bacteria in the pores. Shaving or plucking hairs can increase the risk of bacterial folliculitis. Symptoms include tiny, red bumps and/or white-headed pimples filled with pus. Folliculitis tends to affect people with acne more than those with clearer skin. Left untreated, folliculitis can cause permanent hair loss.
- Boils (furuncles) or furunculosis develop when the infection spreads further into the follicle and reaches the hair shaft, and sebaceous gland. It begins as a red, tender lump that rapidly fills with pus as it gets bigger. It can be painful. It’s common on the face, neck, armpits, buttocks, and thighs. Left untreated, it can become an abscess.
- Ecthyma is a skin infection that starts in skin that has been injured due to a scratch, rash, or insect bite. It often develops on the legs. Similar to impetigo, its often called deep impetigo.
- Small skin abscesses (pus-filled pockets in the skin) can appear anywhere on the body. They look like boils, but larger. They can also be more painful. Abscesses can make you sick with a fever.
- Carbuncles is a cluster of boils closely packed together that has one or more openings where pus can ooze out. (The infection may also cause a fever, fatigue, and a general feeling of unwellness). They usually develop on the back, thighs, or back of the neck. The infection can be deeper and more severe than boils, and there’s a greater risk that it can be spread to other parts of the body and can take longer to resolve.
More serious bacterial skin infections – also known as acute bacterial skin and skin structure infections (ABSSSIs) – include:
- cellulitis
- erysipelas
- large skin abscesses
- necrotising skin infections (causing patches of tissue to die)
- wound infections
Furthermore, bacterial infections in the body can have skin-related consequences like Staphylococcal-scalded skin syndrome, scarlet fever, and toxic shock syndrome.
Infections that develop because of the underlying condition of eczema are called secondary infections.
Symptoms
The symptoms will depend on the type of infection the person has. Symptoms common to many bacterial infections include:
- red painful skin, sometimes around a cut, scrape or other skin injury (inflammation)
- pus or fluid leaking out of the skin
- a painful, red, warm lump under the skin
- crusting or blisters with redness on the skin
- itching
- blisters
Causes
Bacterial skin infections are caused by a wide range of bacteria, and most commonly by Staphylococcus aureus (“Staph”) and Streptococcus pyogenes (“Strep”) or even by both organisms. Methicillin-Resistant Staph Aureus (MRSA) can also cause any of the infections listed above (impetigo, folliculitis, furuncles, abscesses, and cellulitis), however because Methicillin and other antibiotics (usually used to treat Staph infections) do not work on this type of Staph, other antibiotics must be used.
Less common bacteria may also be spread in hospitals, nursing homes, the soil, oceans or ponds.
How are bacterial skin infections spread
- Bacteria can enter the skin through hair follicles or through small breaks in the skin that result from scrapes, punctures, burns, sunburn, animal or insect bites, wounds, eczema, shaving, other preexisting skin disorders and surgery. Soft skin tissue infections are common healthcare-associated infections among those who have undergone surgery.
- Most bacterial skin infections are contagious and can be spread by skin contact with someone who has the infection.
- Hot tubs or heated swimming pools that are not well treated may have bacteria that can cause “hot tub folliculitis”.
- It’s normal to have some bacteria in your nose, including Staph bacteria. This is called being “colonised”. This usually causes no symptoms in the nose but can lead to skin infections.
Risk factors
Any break in the skin predisposes a person to infection. However, certain people are at particular risk:
- People with preexisting skin conditions such as eczema or acne
- People with diabetes, who are likely to have poor blood flow and have a high level of sugar (glucose) in their blood, which decreases their ability to fight infections
- People who are bedridden, paralysed, or have to stay in the same position for a long time
- People older than the age of 65
- 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.
- People who are malnourished
- People who have excessive skinfolds (in the case of obesity)
- Children under the age of 5
Diagnosis
Bacterial skin infections are usually diagnosed by healthcare professionals on how they look and what your symptoms are. Sometimes a skin culture test is taken by rubbing a swab on the crust, scab, liquid, or pus; the culture will show which type of bacteria is causing the infection, so that the right antibiotic can be prescribed. Additionally, some providers may also use blood tests.
Treatment
Treatment includes:
- Antibiotics. For minor infections, an antibiotic ointment is used. Ointments such as Mupirocin are indicated for the treatment of primary and secondary bacterial infections caused by Staphylococcus aureus and other susceptible organisms.
- If a larger area of the skin is infected, you may be prescribed oral antibiotics or an injection.
- Drainage of abscesses. For abscesses, they should be cut open by a doctor, drained, and any dead tissue should be surgically removed.
- Severe bacterial skin infections may be treated in hospitals if the person requires oral or intravenous antibiotics.
Complications
Bacterial skin infections may cause the following complications:
- Breaking down of the skin
- Scarring or post-inflammatory hyperpigmentation
- The development of abscesses
- Rheumatic fever (may result from Streptococcal skin infection)
- Recurrent infections
- Infections due to resistant bacteria, such as MRSA, may be more difficult to treat.
- Sepsis – the body’s extreme response to an infection. This is life-threatening and can rapidly cause tissue damage, organ failure, and even death.
- Septic embolism – this is an infection (typically a bacterial infection), which starts in a blood vessel and then travels to other parts of the body. An infection of the heart can lead to a blood clot that travels to the brain, which may result in a stroke, cerebral haemorrhage, meningitis, brain abscess, or a mycotic aneurysm.
When to see a doctor
If you experience any of the following, please see a health care professional:
- Pus-filled blisters
- Widespread swelling/inflammation
- Red streaks spreading out from the infected area
- Fever, feeling unwell
- The skin infection isn’t getting better or gets worse
- Frequent or recurring infections
Living and managing
Here are some suggestions for caring for your skin infection at home:
- Use over-the-counter antihistamines to reduce itching.
- Use topical creams and ointment to reduce itching.
- Apply cold compresses to the skin several times a day to reduce inflammation.
Prevention
The best way to prevent bacterial skin infections is to keep the skin clean and undamaged.
- Keep hands clean by washing with soap and water. Alternatively, use hand sanitiser and rub hands together until they are dry.
- Avoid sharing personal items, such as towels, loofahs, and razors.
- Before using a hot tub or heated pool, ensure that the temperature and chlorine is checked frequently.
- After swimming, remove swimsuits and shower.
- Shower after sports.
- Clean frequently-touched surfaces – such as doorknobs and counters – in the house regularly.
- Check pets for skin infections and treat them accordingly.1
- Do not use antibiotic ointments (prescription or nonprescription) on uninfected minor wounds because of the risk of developing an allergy to the antibiotic.
- For people living with eczema: Use antiseptic washes or creams to reduce the amount of Staph. aureus on the skin. Commonly these antiseptics are triclosan, chlorhexidine gluconate or sodium hypochlorite. These antiseptics come combined with emollient preparations and can be used to wash with in the bath or shower, or applied as a leave-on preparation. Antiseptics do not create bacterial resistance.2
- For people who experience recurrent infections:
- Consider bleach bathing which uses the chemical sodium hypochlorite, which is effective against bacteria, fungi, viruses, and MRSA. The principle of bleach bathing is to bathe in the bleach solution twice a week, and continue with your usual treatment routine in between.2
- Apply antibiotic ointment inside the nose of the person getting infections. Family members or close contacts may also carry Staph bacteria inside the nose even without a history of infections and they need to be treated too.1
References
Footnotes
1 The Society for Pediatric Dermatology.
2 National Eczema Society
References
- Brannon, H.L. (2023). 9 Infections That Cause a Bacterial Skin Rash. Very Well Health [Online]. Accessed on 13 July 2023.
- Centers for Disease Control & Prevention. (2022). What is Sepsis?. CDC [Online]. Accessed on 17 July 2023.
- DePietro, M. (2023). What To Know About Skin Infection Types, Causes, and Treatment. Healthline [Online]. Accessed on 17 July 2023.
- Duncan, N. & Whittaker, L. (2023). Bacterial skin infections. DermNet [Online]. Accessed on 13 July 2023.
- Johns Hopkins Medicine. (n.d.). Other Bacterial Skin Infections. Johns Hopkins Medicine [Online]. Accessed on 13 July 2023.
- MedlinePlus National Library of Medicine. (2023). Skin Infections. Medline Plus. [Online]. Accessed on 13 July 2023.
- MedlinePlus National Library of Medicine. (2021). Ecthyma. Medline Plus. [Online]. Accessed on 13 July 2023.
- Meštrović, T. (2022). B.Sc.Bacterial Skin Infections: What are they?. News Medical Life Sciences [Online]. Accessed on 13 July 2023.
- National Eczema Society. (2021). Infections and eczema factsheet. National Eczema Society [Online]. Accessed on 13 July 2023.
- Rehmus, W.E. (2023). Overview of Bacterial Skin Infections. Merck Manuals [Online]. Accessed on 13 July 2023.
- Richards, L. (2023). What to know about bacterial skin infections. Medical News Today [Online]. Accessed on 17 July 2023.
- The Society for Pediatric Dermatology. Bacterial skin infections. American Academy of Dermatology [Online]. Accessed on 13 July 2023.
- Vega, J. (2021). Septic Embolism Causes, Symptoms, and Diagnosis. Very Well Health [Online]. Accessed on 17 July 2023.
References
Footnotes
1 The Society for Pediatric Dermatology.
2 National Eczema Society
References
- Brannon, H.L. (2023). 9 Infections That Cause a Bacterial Skin Rash. Very Well Health [Online]. Accessed on 13 July 2023.
- Centers for Disease Control & Prevention. (2022). What is Sepsis?. CDC [Online]. Accessed on 17 July 2023.
- DePietro, M. (2023). What To Know About Skin Infection Types, Causes, and Treatment. Healthline [Online]. Accessed on 17 July 2023.
- Duncan, N. & Whittaker, L. (2023). Bacterial skin infections. DermNet [Online]. Accessed on 13 July 2023.
- Johns Hopkins Medicine. (n.d.). Other Bacterial Skin Infections. Johns Hopkins Medicine [Online]. Accessed on 13 July 2023.
- MedlinePlus National Library of Medicine. (2023). Skin Infections. Medline Plus. [Online]. Accessed on 13 July 2023.
- MedlinePlus National Library of Medicine. (2021). Ecthyma. Medline Plus. [Online]. Accessed on 13 July 2023.
- Meštrović, T. (2022). B.Sc.Bacterial Skin Infections: What are they?. News Medical Life Sciences [Online]. Accessed on 13 July 2023.
- National Eczema Society. (2021). Infections and eczema factsheet. National Eczema Society [Online]. Accessed on 13 July 2023.
- Rehmus, W.E. (2023). Overview of Bacterial Skin Infections. Merck Manuals [Online]. Accessed on 13 July 2023.
- Richards, L. (2023). What to know about bacterial skin infections. Medical News Today [Online]. Accessed on 17 July 2023.
- The Society for Pediatric Dermatology. Bacterial skin infections. American Academy of Dermatology [Online]. Accessed on 13 July 2023.
- Vega, J. (2021). Septic Embolism Causes, Symptoms, and Diagnosis. Very Well Health [Online]. Accessed on 17 July 2023.