What Common Skin Infections Look Like

Recognizing rashes and lesions caused by bacteria, viruses, or fungi

Although one important function of the skin is to help protect the body from harmful microbes, sometimes it can become the target of infection-causing bacteria, viruses, or fungi. When this happens, there will invariably be a change in the appearance of the skin, such as a lesion or a rash.

Often, it's possible to recognize a particular skin infection based on what it looks like and the area of the infection, so it can be helpful to be familiar with the visible symptoms of common ones.



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Chickenpox is a skin infection caused by the varicella-zoster virus. Early in a chickenpox infection, the rash is characterized by clusters of vesicles (small sacs filled with fluid) on an erythematous (reddened skin) base.

These distinctive lesions, which have been described as "dewdrops on a rose petal," are preceded by flu-like symptoms. They usually crop up first on the face, chest, and back, and then spread to other parts of the body. Within a few days of appearing, the clusters of vesicles grow together to make larger lesions that crust and scab.

Chickenpox is highly contagious. It spreads easily through skin-to-skin contact as well as by breathing in infected droplets sent into the air when someone sick with the virus coughs or sneezes.

Once considered a common childhood illness, the incidence of chickenpox has declined dramatically since the varicella vaccine was introduced in 1995.


Fungal Nail Infection

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nail fungus in whit

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Thickened, discolored toenails and fingernails are often due to a fungal infection of the nail bed (the skin beneath the nail), matrix (where the growth of the nail begins), or nail plate (the nail itself) caused by a fungus called Trichophyton rubrum. The medical terms for such infections are onychomycosis or tinea unguium.

Although fungal nail infections are not technically skin infections, they tend to affect the skin surrounding the affected nail. Symptoms include:

  • Separation of the nail plate from the nail bed
  • Discoloration (yellowing, browning, or whitening) of the nail
  • Thickening of the nail
  • Cracking or breaking of the nail

Although oral anti-fungal medication is often the best treatment option, combining oral drugs with topical anti-fungal medication may make treatment more effective.


Cold Sore

cold sore
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Also known as fever blisters, cold sores are lesions that appear anywhere on or around the lips, mouth, or nostrils. They begin as small fluid-filled sacs called vesicles. The vesicles form ulcers that eventually become crusted over before healing and disappearing.

The majority of cold sores are caused by type 1 herpes simplex virus (HSV-1) and are clinically known as oral herpes (herpes labialis). However, some may be caused by type 2 HSV (HSV-2), the same virus that causes genital herpes. It can be transmitted to the mouth by oral sex with someone who has an active genital herpes infection.


Rocky Mountain Spotted Fever

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Rocky Mountain spotted fever
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Rocky Mountain spotted fever (RMSF) is a potentially fatal disease characterized by a rash made up of small, pink, flat spots that most often appear first on the ankles, forearms, and wrists. As the rash progresses, the spots move to the palms, soles of the feet, and trunk.

Around 10% of people infected never develop a rash. For those who do, the spots usually show up around four days into the infection, which is caused by a bacterium called Rickettsia rickettsii.

Rocky Mountain spotted fever is spread via the bite of a tick infected with the bacterium. Although it has appeared throughout the United States, over 50% of cases occur in North Carolina, Virginia, Arkansas, Tennessee, and Missouri.



Impetigo rash beneath a mans lower lip

Impetigo is a bacterial infection of the upper layers of the skin. It can begin as an outbreak of tiny blisters that rupture, ooze fluid, and eventually form a yellow/brown-colored crust. It can be somewhat itchy but rarely causes pain or discomfort.

Impetigo occurs when either Streptococcus bacteria or Staphylococcus bacteria enter the body through a break in the skin, such as a cut, scrape, burn, or insect bite. Children often develop impetigo in warmer months when they're outside more frequently. Besides the face, impetigo can also appear on the arms or legs.

A less common type, called bullous impetigo, leads to the formation of large blisters known as bullae. Diagnosing impetigo sometimes requires a bacterial culture. Topical or oral antibiotics are the typical treatment.



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Tinea corporis infection (ringworm)

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Ringworm, or tinea corporis, is not a worm, but rather a fungal infection. It starts out as a flat, scaly lesion that extends outward in all directions to form a circular shape. Ringworm is so named because the perimeter of the circle is raised and scaly, forming a ring around the central area. Sometimes vesicles develop.

Ringworm rashes tend to be itchy and can cause hair loss if they affect the scalp or other hair-bearing areas and are not treated. Thanks to its distinctive appearance, ringworm is easily diagnosed and can be effectively treated with oral or topical medications.


Ingrown Toenail

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ingrown nail.

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An ingrown toenail usually occurs due to prolonged pressure of the nail against the skin of the toe. The nail grows partially into the skin, piercing it and causing irritation, pain, and swelling.

While not an infection in and of itself, an ingrown toenail can become infected when bacteria invade the broken skin. In that case, the skin around the nail will become red and swollen; there may also be drainage of pus.

Treatment may include soaking the nail in an Epsom salt foot bath, wearing sandals or shoes with a wide toe box until the toe heals, and using an oral antibiotic to clear up the infection.


Athlete's Foot


Athlete's foot, or tinea pedis, is a common fungal infection that affects the feet. There are three types, each of which has a distinctive appearance:

  • Chronic interdigital athlete’s foot: The most common form of athlete's foot, it's characterized by skin dryness and flaking, maceration, and fissures that most often develop between the fourth and fifth toes.
  • Chronic scaly athlete’s foot (moccasin type): Caused by a fungus called Trichophyton rubrum, this type of athlete's foot is characterized by fine, silvery scaling with pink tender skin underneath.
  • Acute vesicular athlete’s foot: Also known as jungle rot, this infection caused by Trichophyton mentagrophytes is characterized by painful blisters on the sole or top of the foot. It sometimes develops in people who have chronic interdigital toe web infection.

Wearing damp socks or tight shoes, or going barefoot in communal areas such as gym showers and public pools, can increase the risk of athlete's foot. Treatment for athlete's foot includes using over-the-counter antifungal creams or sprays or prescription medicines for more severe infections.

A Word From Verywell

There are many types of skin infections but the one thing all have in common is they can be unsightly, uncomfortable, and even painful. Most are easy to identify and treat; rarely is a skin infection a serious threat to overall health.

It's important to have any lesion, rash, or change in the appearance of skin checked by a doctor without delay, however, as these sometimes can be symptoms of skin cancer.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Chickenpox (Varicella): Signs and symptoms.

  2. Denny JT, Rocke ZM, McRae VA, et al. Varicella pneumonia: case report and review of a potentially lethal complication of a common diseaseJ Investig Med High Impact Case Rep. 2018;6:2324709618770230. doi:10.1177/2324709618770230

  3. Pang SM, Pang JYY, Fook-Chong S, Tan AL. Tinea unguium onychomycosis caused by dermatophytes: a ten-year (2005-2014) retrospective study in a tertiary hospital in SingaporeSingapore Med J. 2018;59(10):524–527. doi:10.11622/smedj.2018037

  4. Cleveland Clinic. Toenail fungus.

  5. Cleveland Clinic. Genital herpes (HSV-2).

  6. Centers for Disease Control and Prevention. Rocky Mountain spotted fever (RMSF): Signs and symptoms.

  7. Centers for Disease Control and Prevention. Rocky Mountain spotted fever (RMSF): Epidemiology and statistics.

  8. Cleveland Clinic. Impetigo.

  9. Centers for Disease Control and Prevention. Fungal diseases: Ringworm.

  10. Cleveland Clinic. Ingrown toenails.

  11. MedlinePlus. Athlete's foot.

By Heather L. Brannon, MD
Heather L. Brannon, MD, is a family practice physician in Mauldin, South Carolina. She has been in practice for over 20 years.