Fungal Infections of the Skin

Medically Reviewed by Stephanie S. Gardner, MD on March 06, 2024
5 min read

A fungal infection, also called mycosis, is a skin disease caused by a fungus.

There are millions of species of fungi. They live in the dirt, on plants, on household surfaces, and on your skin. Sometimes, they can lead to skin problems like rashes or bumps.

A fungal skin infection might cause:

  • Irritation
  • Scaly skin
  • Redness
  • Itching
  • Swelling
  • Blisters

Fungal skin infections can happen anywhere on your body. Some of the most common are athlete's foot, jock itch, ringworm, and yeast infections.

Athlete's foot, also called tinea pedis, is a fungal infection of your foot.

The fungi grow best in warm, moist places such as shoes, socks, swimming pools, locker rooms, and public showers. They’re often found in the summer and in hot, humid climates. It happens more often in people who wear tight shoes, who don’t change their sweaty socks, and who use public baths and pools.

Athlete's foot causes

The fungi behind athlete’s foot live on the dead tissue of your hair, toenails, and outer skin layers. At least four kinds of fungus can cause the infection. The most common is Trichophyton rubrum.

Athlete's foot symptoms

Signs of athlete's foot vary from person to person. You might have:

  • Peeling, cracking, and scaly feet
  • Blisters
  • Skin that’s red, softened, or broken down
  • Itching
  • Burning

Types of athlete's foot

  • Interdigital. This is also called toe web infection. Most people with athlete’s foot have this form. It usually occurs between your two smallest toes. The infection can spread to the sole of your foot.
  • Moccasin. This form can begin with irritation, dryness, itching, or scaly skin. Over time, your skin may thicken and crack. This infection can involve your entire sole and extend onto the sides of your foot.
  • Vesicular. This is the rarest kind of athlete's foot. It usually begins with a sudden outbreak of fluid-filled blisters, often on the underside of your foot. They also can appear between your toes, on your heel, or on top of your foot.

Athlete's foot diagnosis

Not all itchy, scaly feet are caused by a fungus. Your doctor may scrape off a bit of skin and look at it under a microscope to check for a different condition.

Athlete's foot treatment

Your doctor might give you antifungal medicine to put on your skin or, in severe cases, another kind to take by mouth. Be sure to keep your feet clean and dry.

Athlete's foot prevention

To keep from getting athlete’s foot, wear shower sandals in public showering areas, wear shoes that let your feet breathe, and wash your feet every day with soap and water. Dry them thoroughly, and use a quality foot powder.

A type of fungus called tinea causes jock itch. The infection is also known as tinea cruris. Tinea loves warm, moist areas like your genitals, inner thighs, and buttocks. Infections happen more often in the summer or in warm, wet climates.

Jock itch is a red, itchy rash that’s often ring-shaped.

Is jock itch contagious?

It’s only mildly contagious. It can spread from person to person through direct contact or indirectly through objects with the fungus on them.

Jock itch symptoms

Symptoms of jock itch include:

  • Itching, chafing, or burning on your groin or thigh
  • A red, circular, rash with raised edges
  • Redness on your groin or thigh
  • Flaking, peeling, or cracking skin

Jock itch diagnosis

Doctors can usually diagnose it by what it looks like and where it is on your body. They might look at a sample of skin under a microscope to be sure.

Jock itch treatment

Keep the affected area clean and dry. Over-the-counter antifungal medicines can treat most cases of jock itch. In severe cases, your doctor might need to give you a prescription cream. No matter your treatment, be sure to:

  • Wash and dry the area with a clean towel
  • Use the antifungal medicine as directed
  • Change clothes -- especially your underwear -- every day

Ringworm, also called tinea corporis, isn’t a worm but a fungal skin infection.  It’s named for its ring-shaped rash with a winding, worm-like edge.

Is ringworm contagious?

Ringworm can spread through direct contact with infected people or animals. You can also pick it up off clothing or furniture. Heat and humidity can help spread the infection.

Ringworm symptoms

Ringworm is a red, circular, flat sore that can happen along with scaly skin. The outer part of the sore might be raised while the skin in the middle appears normal. Patches or red rings may overlap.

Ringworm diagnosis

Your doctor can diagnose ringworm based on your symptoms. They might ask whether you’ve come into contact with infected people or animals. They might also take samples from the area and look at them under a microscope to be sure.

Ringworm treatment

Treatment usually involves antifungal medications that you put on your skin. You might use an over-the-counter cream such as:

  • Clotrimazole (Lotrimin, Mycelex)
  • Miconazole (Micatin, Monistat-Derm)
  • Terbinafine (Lamisil)

In more severe cases, you might need prescription medications to put on your skin or take by mouth.

Yeast infections of your skin are called cutaneous candidiasis. A type of fungus called candida causes these infections when it grows too much. Yeast infections aren’t contagious.

The infections are most common in warm, moist, creased areas of your body, including your armpits and groin. They often happen in people who are obese or who have diabetes. People taking antibiotics are also at higher risk.

Candida can cause diaper rash in infants. It can also cause infections in your nails, vagina, or mouth (oral thrush).

Yeast infection symptoms

Signs of a yeast infection on your skin include:

  • Rash
  • Patches that ooze clear fluid
  • Pimple-like bumps
  • Itching
  • Burning

Signs of a yeast infection in your nail beds include:

  • Swelling
  • Pain
  • Pus
  • A white or yellow nail that separates from the nail bed

Signs of thrush (yeast infection of your mouth) include:

  • White patches on your tongue and inside your cheeks
  • Pain

Signs of a vaginal yeast infection include:

  • White or yellow discharge from your vagina
  • Itching
  • Redness in the external area of your vagina
  • Burning

Yeast infection diagnosis

Your doctor will ask about your medical history and do a physical exam. They might also take a sample from the affected area to look at under a microscope.

Yeast infection treatment

Treatment depends on the infection. Medicated creams can treat most skin yeast infections. For a vaginal infection, you can usually use medicated suppositories. A medicated mouthwash or lozenges that dissolve in your mouth may treat oral thrush. If you have a severe infection or a weakened immune system, you might need anti-yeast medications that you take by mouth.