Fungal Infections of the Skin

Medically Reviewed by Zilpah Sheikh, MD on June 12, 2024
Written by Alyson Powell Key
8 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 such as rashes or bumps.

Bacterial vs. fungal skin infections

The key difference between bacterial and fungal infections is how doctors treat them. You'll take an antifungal medicine for a fungal infection, which could take a while to treat. Doctors prescribe antibiotics to treat bacterial infections, and these medicines work more quickly.

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

Athlete's foot, or tinea pedis, is a fungal infection of the foot. Fungi thrive in warm, moist environments such as shoes, socks, swimming pools, locker rooms, and public showers. This infection is more common in people who wear tight shoes, don’t change sweaty socks, and use public baths and pools. The fungi responsible for athlete’s foot live on the dead tissue of hair, toenails, and outer skin layers, with Trichophyton rubrum being the most common culprit.

Jock itch

Jock itch is also known as tinea cruris. A type of fungus called tinea causes this infection. This fungus thrives in warm, moist areas such as the genitals, inner thighs, and buttocks. Infections are more common during the summer or in warm, wet climates. Jock itch appears as a red, itchy, ring-shaped rash.

Jock itch is only mildly contagious, spreading through direct contact or indirectly via objects carrying the fungus. Symptoms include:

  • Itching, chafing, or burning in the groin or thigh area
  • A red circular rash with raised edges, redness
  • Flaking, peeling, or cracking skin

Ringworm

Ringworm, or tinea corporis, is a fungal skin infection named for its ring-shaped rash with a worm-like edge. Ringworm is contagious and can spread through direct contact with infected people or animals or by touching tainted clothing or furniture. Heat and humidity can help the spread of the infection. Symptoms include a red, circular, flat sore with scaly skin — where the outer part of the sore might be raised, while the middle appears normal. Red rings or patches may overlap.

Yeast infections

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. They're most common in warm, moist, creased areas of your body, including your armpits and groin. They often happen in people with obesity or diabetes. Also, if you're taking an antibiotic, you are more likely to get a yeast infection.

Onychomycosis

Onychomycosis is a fungal infection that affects the nails on your fingers or toes. It causes your nails to become discolored, thickened, and sometimes separate from the nail bed. The condition is more common in older adults due to issues such as poor blood flow, immune system problems, and diabetes. Onychomycosis impacts toenails more often than fingernails because they grow more slowly, have less blood flow, and are usually in dark, moist conditions.

You're more likely to get a fungal skin infection if you:

  • Come into contact with an infected person or animal
  • Borrow shoes or clothes that contain harmful fungus
  • Take long-term or high-dose antibiotics
  • Are overweight
  • Have diabetes
  • Sweat a lot 
  • Have a weakened immune system
  • Live in a warm or wet environment
  • Wear tight clothing or footwear that doesn’t breathe well
  • Try a new skin product

To treat a fungal skin infection, you'll need antifungal medications, which can be topical (applied directly to your skin) or tablets (oral).

Topical antifungals

These medications come as creams, lotions, and shampoos. You can usually buy them from a pharmacist without a doctor’s prescription. Examples include:

  • Clotrimazole (Canesten)
  • Miconazole (Daktacort and Daktarin)
  • Terbinafine (Lamisil)

You may need to continue treatment for fungal nail infections for up to a year. For other types of infections, you should add up to 2 weeks of treatment after your symptoms have disappeared to make sure the infection doesn’t return.

Always read the leaflet with your medication and ask a pharmacist any questions.

Antifungal tablets

If your infection doesn't get better after using an antifungal, it covers a large part of your skin or affects your nails or scalp, your doctor may prescribe antifungal tablets. Examples of antifungal tablets include:

  • Griseofulvin
  • Itraconazole
  • Terbinafine (Lamisil)

You'll take this medicine for up to 6 months to completely get rid of your infection.

Here are steps you can take to lower your chances of getting a fungal skin infection:

  • Dry yourself completely after showering or bathing, especially between your toes and in skin folds where moisture can get trapped.
  • Avoid walking barefoot in public places such as locker rooms, showers, and pools where fungus can spread.
  • Wear loose-fitting clothing made from cotton or other materials that let your skin breathe.
  • Avoid sharing towels, hats, brushes, or combs with others.
  • If you often get athlete's foot, switch your shoes every few days to let them dry out completely. Wear sandals or open shoes in hot weather.
  • People with diabetes should keep their blood sugar levels under control, as this can help prevent fungal infections.
  • If someone in your family has ringworm on their scalp, wash or throw away any bedding, hats, combs, or other items they might have touched to prevent spreading the infection.
  • If you think your pet has ringworm, take them to the vet for treatment to avoid catching it yourself.

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, don’t change their sweaty socks, and use public baths and pools.

Athlete's foot causes

The fungi that cause 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 to 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 such as your genitals, inner thighs, and buttocks. Infections happen more often in the summer or 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.

Fungal infections, or mycoses, are skin diseases caused by various fungi that live in warm and wet environments. Common types include athlete's foot, jock itch, ringworm, and yeast infections, each presenting with specific symptoms such as itching, redness, and rashes. These infections are often not serious but can be irritating and are easily spread through direct contact or shared items. Prevention involves good hygiene practices, such as keeping skin clean and dry, avoiding sharing personal items, and wearing protective footwear in public areas. Treatment typically involves topical antifungal medications, with more severe cases requiring oral antifungals.