Ringworm is a common fungal infection that can affect several areas of the body, including the scalp, feet, groin, other areas of skin, and also the nails. The specific type of fungus that causes ringworm (which is also known as tinea) grows in moist, warm environments.

Tinea lives on the outermost layer of the skin, hair and nails and feeds on the cells there. As the fungus multiplies on the skin, it spreads out in a circle, leaving a distinctive ring-like pattern. Despite its name, there is no worm present under the skin in patients with this infection.

Ringworm is contagious, and people can become infected with the causative fungus in many ways. Direct contact with an infected person or animal can transmit the fungus. Direct contact with contaminated, damp surfaces (e.g., public showers, locker room floors) and other contaminated items (e.g., combs, unwashed clothing) also can result in ringworm infection.

Ringworm is a skin disorder that can affect people of all ages. People with compromised immune systems are more vulnerable to ringworm infection. Other skin conditions (e.g., atopic dermatitis, psoriasis) sometimes can cause symptoms similar to those of ringworm. For this reason, a physician typically performs various tests to make a definitive diagnosis of ringworm.

Some ringworm infections may get better on their own without any treatment. Patients with minor symptoms also may be able to get rid of ringworm using simple self-care measures. In other cases, ringworm infections may require treatment with prescription medications such as antifungal creams or pills.

Several steps can be taken to prevent ringworm. People should avoid close contact with people or animals known to be infected with ringworm. People also are urged to keep their skin and feet clean and dry, to shampoo regularly, and to wear sandals or shoes at gyms, lockers and pools. It is best not to share clothing or personal care items such as towels, brushes and combs.

Ringworm is a fairly common fungal infection that can affect several different areas of the body. It is caused by species of fungi called dermatophytes that live on the dead tissues of skin, hair and nails. Some species live preferentially on humans, others on animals.

When people use the term ringworm, they often are referring to the infection that causes a ring-shaped rash and bald spot on the skin (tinea corporis) or scalp (tinea capitis). However, ringworm also can affect the feet (tinea pedis) or the groin (tinea cruris) and other areas of the body.

Normally, a person’s skin cells move from the lowest layer of the skin to the highest layer of the skin over the course of about a month. Once the skin cells reach the outermost layer, they die and scale off in flakes.

The fungus that causes ringworm grows in moist, warm environments. It lives on the outermost layer of the skin, hair and nails and feeds on the cells there. As it multiplies on the skin, it spreads out in a circle, leaving its distinctive ring-like pattern. Despite its name, there is no worm present under the skin in patients with this infection.

Ringworm is contagious, and people may become infected with the fungus from many different sources. Direct contact with an infected person can transmit the fungus. Direct contact with an infected animal’s skin or hair also can cause a person to become infected with ringworm. Animals with ringworm often have a patch of skin where hair is missing. Animals known to transmit ringworm include:

• Cats (especially kittens)
• Dogs (especially puppies)
• Horses
• Ferrets
• Rabbits
• Guinea pigs
• Cows
• Goats
• Pigs

Direct contact with contaminated, damp surfaces (e.g., public showers, locker room floors) and other contaminated items (e.g., combs, unwashed clothing) also can result in ringworm infection. In rare cases, a person can become infected with ringworm after coming into contact with infected soil.

People infected with ringworm are at risk for several complications. Ringworm may spread from the source of origin to other areas of the body. Ringworm is also associated with bacterial skin infections (from scratching the skin with dirty nails) and certain types of skin rashes (e.g., contact dermatitis). Symptoms of these conditions are similar to those of ringworm, except that bacterial skin infections may also include fever.

Ringworm involves infection with the dermatophyte fungus. This fungus can affect various areas of the body. Some experts classify all of these infections as ringworm, while other authorities use the term to apply only to infections of certain areas, such as the skin or scalp. The location of the body affected by the fungus determines the name given to the infection, such as:

• Tinea capitis. Occurs on the scalp and often leaves bald patches in the affected areas.  One or more lesions may appear on the scalp, with or without inflammation. Baldness is usually reversible and may occur in patches or affect the entire scalp. The longer the infection persists, the more likely the hair loss will be permanent. Swollen, raw and pus-filled lesions (pustules) may develop. This type of ringworm may also be further classified as follows:
  
  
• • Black dot type. Begins as a small patch that slowly enlarges. There is no itching, but there is redness. Hairs break off at the scalp and particles accumulate in the follicle openings, appearing as black dots. If left untreated, scars may form.
    
    
  • Gray patch type. Begins as a small patch that spreads for a while then stops spreading and persists. Redness and scaling are present. Hairs break off just above the scalp level and have a frosted appearance.
    
    
• Tinea corporis. Occurs on the top layer of skin on the arms, legs, trunk or face and appears as red, flat or slightly raised circular sores that may be intensely itchy. These may be dry and scaly or crusted and moist, and may be accompanied by tiny blisters or solid bumps (papules). As the sores become bigger, the center tends to clear, leaving seemingly normal skin surrounded by an infected edge.
  
  
• Tinea cruris. Usually involves infection of the groin and is commonly known as jock itch. It may also affect the inner thighs and buttocks. The condition is more common in men than in women and is often transferred from a person’s infected foot to the groin area (e.g., during dressing). The scrotum and penis are usually not affected. The borders of the rash are well-defined and scaly and may contain blisters or pustules. The rash increases in size over time.
  
  
• Tinea pedis. Usually involves infection of the skin between the toes and is often called athlete’s foot. In some cases, infection may occur on the foot itself. Typical symptoms include scaling of the skin between the toes, especially the fourth and fifth toe, with itchiness and possibly soreness. It often spreads over the sole and instep of the foot. It may later spread onto the sides or top of the foot and in severe, untreated cases, even over the ankle and leg. Small, fluid-filled blisters may also be present and the border between affected and unaffected skin tends to be very distinct. Athlete’s foot is typically more severe in hot weather, when wearing heavy footwear or when perspiring excessively. One or both feet may be affected. Chronic forms tend to be gradually progressive whereas acute forms may be very sudden and tend to be intensely itchy or even painful.

Ringworm is a relatively common fungal infection that can affect people of all ages. However, most types of ringworm are more common among children than adults. Outbreaks may occur in infant nurseries, daycare centers and schools.

Ringworm is most likely to occur when a person’s skin, scalp or nails are persistently wet (e.g., from sweating) or when minor injuries occur in these areas of the body. People living in humid environments are at increased risk of contracting ringworm.

People with compromised immune systems also are more vulnerable to ringworm infection. This includes patients with diabetes, HIV and AIDS. Having certain skin conditions may also increase the risk of contracting ringworm. This includes atopic dermatitis, also known as eczema, which appears as itchy, inflamed patches of skin.

To diagnose ringworm, a physician will begin by performing a physical examination and compiling a thorough medical history of the patient.

Because other skin problems (e.g., atopic dermatitis, psoriasis) may cause symptoms similar to those of ringworm, certain tests may be required to definitively diagnosis ringworm. For example, the fungus that causes ringworm may appear fluorescent when examined under an ultraviolet light called a Wood’s lamp. In some cases, a sample of the patient’s skin at the affected site may be scraped off (or a small piece of hair or nails clipped off) and examined under a microscope. In other cases, the sample may be sent to a laboratory, where the sample will be cultured (procedure in which conditions are controlled to allow for the reproduction and growth of potential pathogens in a tissue sample). If the fungi that causes ringworm appears in that cultured sample, a patient can be diagnosed as having a ringworm infection.

Several steps can be taken to prevent ringworm. People should avoid close contact with people or animals known to be infected with ringworm. Checking pets for areas of hair loss can help spot a fungal infection in an animal. Pets with signs of ringworm should be brought to a veterinarian.

Other tips for preventing ringworm include:

• Keep skin clean and dry. Hands and feet should be washed with soap and dried thoroughly after bathing, especially between the fingers and toes.
  
  
• Wear clean socks and underwear every day. Change socks at least once a day. People who sweat a lot are encouraged to change their socks more frequently.
  
  
• Alternate shoes daily to let them air out. Shoes should also be taken off sporadically throughout the day, especially after exercise.
  
  
• Wear comfortable clothes and shoes. Shoes that are well ventilated (e.g., open-toe shoes) and shoes made of natural material, such as leather, are preferable to those that are lined with plastic. Shoes should also provide good support and have a wide toe area. Loose-fitting clothing is preferred over tight clothes.
  
  
• Avoid rough, textured clothing that may chafe the skin.
  
  
• Use separate nail clippers on infected toes or fingernails to prevent the spread of infection.
  
  
• Do not use other people’s personal items, including:
  
  
• Clothes
• Towels
• Sports equipment
• Toiletries
  
  
• Only use facilities that are cleaned and disinfected daily, including:
  
  
• Locker room
• Gymnasium
• Public swimming pool
  
  
• Avoid walking barefoot in public places (e.g., public shower, public pool). Instead, wear flip-flops or sandals.
  
  
• Maintain a healthy weight. Being overweight can lead to skin folds that provide a moist and warm environment ideal for fungi growth.
  
  
• Use topical antifungal powders as needed.
  
  
• Treat illnesses promptly.

Preparing questions in advance can help patients to have more meaningful discussions with their physician regarding their conditions. Patients may wish to ask their doctor the following questions related to ringworm:

1. Do my symptoms indicate that I have ringworm?
   
   
2. What type of ringworm do I have?
   
   
3. What precautions should I take to avoid spreading the infection to others?
   
   
4. What can I do to prevent the infection from spreading to other parts of my body?
   
   
5. What are my treatment options?
   
   
6. How long will treatment last?
   
   
7. What are the potential side effects of my treatment?
   
   
8. When can I expect to see an improvement in my skin?
   
   
9. Is it likely I will develop ringworm again in the future?
   
   
10. What can I do to avoid getting another infection after this one is cured?

Ringworm usually appears as a circular rash with sharply defined edges. These edges are dark red, with more normal-looking skin near the center. This ring-like appearance is characteristic of a ringworm infection.

More than one rash may appear on the skin, and these rashes can sometimes overlap. Rashes and other symptoms of ringworm may occur on several different areas of the body at the same time. Affected areas tend to be itchy. They may also be dry and scaly, or wet and crusty.

Additional symptoms associated with ringworm may vary, depending on the location of the rash on the body. For example, when ringworm affects the scalp or beard, the patient develops a sore resembling a pimple that gradually turns into a bald spot of scaly skin. Ringworm of the nails creates discolored, thick, crumbly nails. Ringworm of the skin starts as a red, scaly patch or bump that begins to resemble a ring or series of rings. Ringworm of the foot or groin often appears as red, scaly patches of skin.

Some patients infected with ringworm do not experience any symptoms at all.

Some ringworm infections may get better on their own without any treatment. Patients with minor symptoms also may be able to get rid of their ringworm with simple self-care measures. These include keeping the skin clean and dry, washing sheets and nightclothes daily during the period of infection, and using over-the-counter antifungal medications. However, patients should not use these medications without first consulting a physician.

In other cases, ringworm infections may require treatment with prescription medications such as antifungal creams or oral medications. Oral drugs may have to be taken for extended periods of time for treatment to be effective. In addition, oral medications may cause side effects in some patients, including gastrointestinal upset, rash and abnormal liver function. It typically takes about one month before medications completely remove the fungi causing ringworm from the body. It may take additional time for the affected area to heal properly and for hair to grow back.

Antibiotics may be prescribed to help treat bacterial skin infections that may occur as a complication of ringworm.