Various pathogens can cause skin infections, such as bacteria, viruses, fungi, and parasites. The symptoms, treatment, and outlook will depend on the cause.

Infections can vary from mild to serious. Most skin infections are highly treatable. However, an infection can become more serious if it goes deeper into the skin or spreads across much of the body.

People with a weakened immune system have a higher risk of skin infections and complications from skin infections. This could be due to:

  • a health condition, such as HIV, diabetes, poor circulation, or malnutrition
  • a side effect of medication, such as chemotherapy or biologic drug use
  • being older or very young
  • have skin folds due to obesity

Over-the-counter medications and home remedies can often treat mild infections, but other infections may need medical attention.

Read on to learn more about skin infections and what to do if you have one.

Here are some pictures of some symptoms of various skin infections:

The following are four different types of skin infections:

1. Bacterial skin infections

Bacterial skin infections occur when bacteria enter the skin, either from an outside source or because they are present on the skin. They can enter the skin through a hair follicle or after a wound.

Anthrax is one type of bacterium that can enter from the environment. Staphylococcus and Streptococcus are bacteria that are commonly present on the skin and only cause a problem in certain circumstances. Lyme disease is a tick-borne infection that causes skin symptoms.

Bacterial infections can be systemic or local. Systemic infections can cause symptoms throughout the whole body, such as a fever, while local infections only affect a specific area. Some bacterial infections can begin in one area and spread throughout the body.

Some bacterial skin infections, such as impetigo, can spread between people through direct skin contact or with bodily fluids, contaminated food or water, or by touching surfaces where bacteria are present. Others, such as cellulitis, are not contagious.

Different types of bacterial skin infections include:

Systemic infections that can cause skin rashes include:

Some bacterial infections are mild and easy to treat with topical antibiotics, but other infections require an oral antibiotic or other medical treatment.

2. Viral skin infections

Viruses can cause different types of infections that have skin symptoms, such as:

These viruses are often contagious, and most are systemic.

3. Fungal skin infections

These types of skin infections are caused by a fungus and are most likely to develop in moist areas of the body where surfaces meet, such as the feet, armpit, or where there are skin folds.

In some cases, an allergy to the fungus causes symptoms in other areas that are not directly affected. For instance, a person with a fungal infection on the foot might develop a rash on their fingers. It doesn’t happen because the person touched their foot.

Different types of fungal infections:

4. Parasitic skin infection

These types of skin infections are caused by a parasite. These infections can spread beyond the skin to the bloodstream and organs. A parasitic infection isn’t life-threatening but can be uncomfortable.

Different types of parasitic skin infections include:

The symptoms of a skin infection will depend on:

  • the type of infection
  • the cause
  • individual factors, such as whether the person has a weakened immune system

Common symptoms of skin infections include:

  • redness on pales skin, or purple or darker areas of skin if you have a darker skin tone
  • lesions that may be flat or raised, bumpy, wart-like, and so on
  • itching
  • pain and tenderness

In some cases, a person may also have other symptoms, such as a fever.

Signs of a severe infection include:

  • pus
  • blisters
  • skin sloughing, breakdown
  • dark areas that can indicate necrosis or tissue death
  • pain and discoloration
  • widespread swelling

Some types of pathogens — notably bacteria and fungi — are typically present on the skin, but if they become too numerous, the immune system can no longer manage them.

In this case, an infection can result.

The cause of a skin infection depends on the pathogen involved.

Bacterial skin infection

These infections occur when bacteria enter the body through a break in the skin, such as a cut or a scratch.

Not all cuts or scratches lead to a skin infection, but there is a higher risk if you:

  • have a weakened immune system
  • do not keep the wound clean
  • are exposed to certain bacteria, for example, when working outside

Viral skin infection

The most common viruses come from one of three groups of viruses:

Experts still don’t know how prevalent viruses are on the skin, unlike bacteria and fungi.

Fungal infection

Body chemistry and lifestyle factors can increase the risk of a fungal infection. Fungi often grow in warm, moist environments.

Some risk factors for a fungal infection are:

  • having sweaty feet or wearing closed footwear
  • wearing sweaty or wet clothes
  • having skin folds due to excess body fat
  • bathing in contaminated water
  • sharing personal items with other people who carry a fungus or have an infection

A break or cut in the skin may allow pathogens to get into the deeper layers of the skin.

Parasitic skin infection

Tiny insects or organisms burrowing underneath your skin and laying eggs can cause a parasitic skin infection.

Examples include:

  • Scabies: An infestation of mites, which causes itching, a rash of small pimples, lines on the skin surface, and scaling or crusty skin.
  • Pediculosis: This is an infection caused by lice. It can cause itching, and lice and nits — their eggs — may be visible.
  • Creeping eruption: Caused by hookworms, this can cause a winding, snake-like rash.

Often, doctors can identify the type of skin infection based on their appearance and location.

The doctor may:

  • ask about symptoms
  • examine any bumps, rashes, or lesions
  • take a sample of skin cells for testing in a laboratory

See a doctor if you have:

  • pus-filled blisters
  • severe or widespread swelling or inflammation
  • a skin infection that doesn’t improve or gets progressively worse
  • a high fever or other symptoms
  • frequent or recurring rashes or infections

Skin infections can spread beyond the skin and into tissues under the skin or the bloodstream, especially in people with a compromised immune system.

When this happens it can lead to sepsis, a potentially life-threatening condition.

Treatment depends on the cause of the infection and the severity.

Some infections will go away on their own or respond to over-the-counter creams.

If an infection is severe, the person is at risk of complications, or the infection is contagious, a doctor may prescribe medication such as:

  • antibiotics
  • antivirals
  • antifungals
  • antiparasitics

The form of the medication will partially depend on the severity of the infection or the risk of complications. A person with a severe infection may need to spend time in the hospital.

Home care and alternative treatments

Home care for a skin infection works to reduce symptoms.

Here are some tips:

The outlook will depend on the cause, type, and severity of the infection.

Many skin infections respond well to medication. However, some conditions, such as methicillin-resistant Staphylococcus aureus (MRSA), are resistant to common antibiotics and harder to treat.

Ways of reducing the risk of a skin infection or rash include:

  • washing regularly
  • drying the body to remove all moisture
  • avoiding sharing personal items with other people
  • checking the skin regularly for changes and seeking advice as soon as signs of an infection appear
  • having the recommended vaccinations to prevent diseases such as chickenpox

What are the five main types of skin infections?

Skin infections can be:

  • bacterial, commonly caused by Streptococcal or Staphylococcal bacteria
  • viral, such as chickenpox or warts
  • fungal, for instance, a yeast infection
  • parasitic, for example, scabies

What does a bacterial skin infection look like?

This will depend on the infection, but it will usually involve inflammation – reddness and swelling.

What is the most common bacterial infection of the skin?

Impetigo is a common example of a bacterial infection. Others include cellulitis and Lyme disease. The most common bacteria associated with skin infections are the Staphylococcus and Streptococcus species.

Skin infections can result from bacterial, viral, fungal, and parasitic causes. The way they affect the body will depend on the specific pathogen. Some cause skin symptoms as part of a wider infection, while others cause local symptoms only.

Skin infections are often highly treatable, but severe symptoms and complications can arise if a person has a weakened immune system.

Some infections are are contagious, such as scabies, and people need to take care not to pass them on before or during treatment.

See your doctor if you have any concerns about signs of a skin infection.