What Is a Staph Infection? Symptoms, Causes, Diagnosis, Treatment ...

What To Know About Skin Infection Types, Causes, And Treatment

We include products we think are useful for our readers. If you buy through links on this page, we may earn a small commission Here's our process.

Healthline only shows you brands and products that we stand behind.

Our team thoroughly researches and evaluates the recommendations we make on our site. To establish that the product manufacturers addressed safety and efficacy standards, we:

Evaluate ingredients and composition: Do they have the potential to cause harm?

Fact-check all health claims: Do they align with the current body of scientific evidence?

Assess the brand: Does it operate with integrity and adhere to industry best practices?

We do the research so you can find trusted products for your health and wellness.

Was this helpful?

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

Is this rash an infection or another skin disorder?

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.

If you need help finding a dermatologist, then check out our FindCare tool here.

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 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 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.

Read this article in Spanish.

Breakthrough Treatment For Skin Infections?

A research team led by Kelvin Yeung from the Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine, the University of Hong Kong (HKUMed) has designed a new microneedle patch that provides an effective non-antibiotic approach for the treatment of skin infections. 

The design engineered with ultrasound-responsive zinc-based metal-organic framework (MOF) antibacterial nanoparticles promises pain-free delivery to treat bacterial infection on skin tissue and facilitate skin repair at the same time. The novel microneedle is around 50 microns in diameter, similar to a typical hair. The findings have been published in Science Advances.

Background

Acne is a common skin disease worldwide affecting more than 80% of teenagers and young adults. This leads to excessive lipid secretion that clogs the hair follicles, thereby establishing a hypoxic microenvironment in skin tissue. This leads to the proliferation of Propionibacterium acnes bacteria. 

It not only causes patients physical and emotional distress, but may also develop into chronic inflammatory conditions without proper treatment. The clinical management normally includes non-prescription treatment (i.E., benzoyl peroxide and salicylic acid), or the administration of antibiotics orally or topically. However, such treatments can be ineffective or have side effects.

Sometimes, drugs can pass through the skin tissue. Also, the treatment becomes less effective when bacteria are drug resistant or when they migrate to subcutaneous tissue. 

Also, P. Acnes bacteria can secrete extracellular polysaccharides to form biofilm that blocks out the attacks initiated by antibacterial agents or immune cells.

Most microneedle products on the market use pharmaceutical ingredients to treat acne. However, repeated applications of antibiotics may reduce the sensitivity of bacteria to drugs. Patients who have been affected by acne for a long time will know that the effects of the same treatment products can be significantly reduced after long-term use.

Research method and findings

The HKUMed team has invented a new microneedle patch that facilitates the transdermal delivery of ultrasound-responsive antibacterial nanoparticles to treat the skin infection induced by P. Acnes at minimal invasive approach. In the current design, ultrasound-responsive antibacterial nanomaterials are introduced to the microneedle patch that respond to bacterial infection quickly and efficiently. The use of drugs is avoided in the treatment. The modified nanoparticles comprised of ZnTCPP and ZnO are able to produce a substantial amount of reactive oxygen species (ROS) subject to ultrasound stimulation that can effectively oxidize the key cellular macromolecules of the bacteria. 

The results demonstrated that the killing of P. Acnes bacteria mediated by ROS can reach 99.73% after 15 minutes of ultrasound stimulation. Also, the levels of inflammatory markers, including tumor necrosis factor-a (TNF-α), interleukins (ILs), and matrix metalloproteinases (MMPs) are significantly reduced. Also, the zinc ions released can elevate the DNA replication-related genes, thereby augmenting more fibroblasts towards better skin repair.

A new approach for addressing skin infections

Kelvin Yeung Wai-kwok said: "The new microneedle patch enabling ROS generation upon ultrasound stimulation, regarding as a non-antibiotic and transdermal approach, can not only effectively address the infection induced by P. Acnes bacteria, but also facilitates the skin repair due to zinc ion release. Due to the specific killing mechanism of ROS, we believe that this design is also able to address the other skin infections induced by fungi, parasites, or viruses, such as tinea pedis."

Looking to expand your network?

Build relationships with world-leading academic teams at 250+ institutes.

A Bacterial Small RNA That Regulates Infection

Infection is a constant risk. Any germs that make it past the body's barriers, like the skin, can cause illness if the immune system does not respond properly and efficiently. Most people can easily fight off common bacteria that could be pathogenic, but people with weaker or compromised immune systems have a greater risk of infection. For the immunocompromised, bacteria like Pseudomonas aeruginosa that are everywhere in the environment can start to grow in different parts of the body, including the lungs; if this occurs, a chronic and even lifelong infection can arise. If bacteria that cause these chronic infections move to the bloodstream, they can become far more serious and even deadly. Scientists are still learning about how bacteria are able to make the transition.

New work has provided insight into how P. Aeruginosa can change from causing one type of infection to another. This study used human samples to reveal a biomarker that indicates when this transition has taken place, in the form of a small RNA generated by the bacterium. The findings have been reported in Nature.

Instead of growing bacteria in the lab, the researchers assessed the bacteria within a human host. They identified all of the genes that the infectious microbes were expressing by sequencing all of the bacterial mRNA.

There are about 6,000 genes in the P. Aeruginosa genome, and one in particular called PA1414 was expressed in human tissues at higher levels than every other bacterial gene combined. This excessive level of expression initially led the investigators to believe there was a problem with their methods.

"This particular gene is not expressed in the standard lab environment very much, so it was striking to see these levels. And at this point, the function of the gene was unknown," said first study author Pengbo Cao, a postdoctoral researcher in the lab of Professor Marvin Whiteley at the Georgia Institute of Technology.

This gene, small RNA SicX (sRNA inducer of chronic infection X), does not encode for any proteins, either. Instead, it appears to be involved in bacterial respiration. Low oxygen levels were found to promote expression of this gene, which is a common part of bacterial infections. Bacteria are usually deprived of oxygen when a chronic infection is underway.

When SicX was eliminated in an animal model of infection, the bacteria quickly moved from chronic infections to cause systemic illnesses. Thus, the gene seems to promote chronic, local infections. When bacterial infections changed from chronic to acute, SicX expression dropped, suggesting that the gene could be a biomarker for this transition.

"In other words, without the small RNA, the bacteria become restless and go looking for oxygen, because they need to breathe like we need to breathe," Whiteley said. "That need causes the bacteria to enter the bloodstream. Now, we know that oxygen levels are regulating this transition."

If clinicians can tell when an infection will change, treatments may improve, along with patient outcomes. A diagnostic test could tell people when treatment is necessary and before their life is threatened, added Whitely, who is corresponding study author.

"The chronic Pseudomonas infection is usually highly resistant to first-line antibiotics," Cao added. "By targeting this small RNA, we could potentially change the lifestyle of the bacteria to make it more susceptible to antibiotic treatments and achieve greater clearance of these dangerous infections."

Sources: Georgia Institute of Technology, Nature

---