The term foot fungus describes superficial fungal infections of the foot. These infections can affect the outer layers of the skin, hair, and nails. Two of the most common foot fungi infections are tinea pedis and onychomycosis.
Keep reading to learn more about these two fungal infections, including potential causes, risk factors, and treatments.
A fungal infection of the foot typically refers to tinea pedis, also known as athlete’s foot or
If a person has a fungal infection of the nail, it is likely onychomycosis, which is also known as tinea unguium.
The fungi or other organism that cause these infections are:
Tinea pedis occurs due to dermatophyte fungi. These are fungi that require keratin for growth and can cause infections on the skin, hair, and nails. The fungi that commonly cause tinea pedis include:
- Trichophyton rubrum
- Epidermophyton floccosum
- Trichophyton interdigitale
Onychomycosis can occur due to the following organisms:
- dermatophytes, such as Trichophyton rubrum, T. interdigitale
- yeasts, such as Candida albicans
- molds, such as Scopulariopsis brevicaulis
Both infections occur in different areas of the foot:
Tinea pedis normally starts in between the toes of the foot. It is particularly common between the 4th and 5th toe space. Some people may use the term athlete’s foot to describe any inflammation between the toes.
Tinea pedis can spread to the sides of the foot and the sole. It can also spread to the heel of the foot. In some cases, tinea pedis can occur in combination with a fungal infection of the groin, hands, nails, or both.
Onychomycosis may involve one toenail or fingernail, or multiple nails. More commonly, onychomycosis affects the big toenail and the little toenail.
The risk factors of both infections may include:
While tinea pedis can occur in anyone, including children and older people, it usually occurs in
Other risk factors for tinea pedis include:
- footwear that covers the entire foot, such as heavy boots or sports shoes
- excessive sweating
- underlying health conditions, such as diabetes
- certain medication, such as corticosteroids or medications that suppress the immune system
- hot and humid environments
- walking barefoot in public areas, such as changing rooms
- wearing socks and shows with poor ventilation
- prolonged exposure to water
- involvement in certain sporting activities, such as expedition adventure racing
Risk factors for onychomycosis include:
- untreated fungal infection
- warm and moist environments
- prolonged water exposure
- previous injury to the nail
- inflammatory diseases of the nail
- certain sporting activities
- excessive sweating
- a suppressed immune system
- inappropriate footwear or socks with poor ventilation
- underlying health conditions, such as diabetes or psoriasis
The symptoms of both infections may include:
Tinea pedis does not have a normal distribution or pattern and can involve just one foot or both feet. It can present in one of three ways:
- itchy, peeling or scaly skin in between the toes, most commonly in the space between the 4th and 5th toes
- scaly skin on the sole and the sides of the feet
- small or medium-sized blisters on the inner part of the foot
While uncommon, a person with tinea pedis may notice oozing in between the toes or ulcers forming.
Other symptoms that a person with tinea pedis may experience include:
- moist, peeling skin
- an unpleasant smell
- thickening of the skin
- the skin discoloring, appearing white, yellow, or green
Symptoms of onychomycosis can include:
- a white or yellow streak on one side of the nail
- scaling under the nail
- the end of the nail lifting and not securely fitting to the toe or finger
- white spots on the nail plate
- damage or destruction of the nail
- discoloration of the nail
- a build-up of debris under the nail
- the nail splitting
- the nail thickening
The diagnosis of both infections may involve:
A doctor will examine a person’s foot and will check for the characteristic signs of tinea pedis. They may also check the groin, hands, and nails to check for any sign of fungal infection in those areas.
The doctor may send skin samples for testing. A scientist will check the scrapings of skin for spores to confirm the presence of fungi.
Further tests may be necessary to confirm a diagnosis. If this is the case, the doctor may send a sample for a fungal culture test
Similarly to tinea pedis, a doctor will examine the affected nail or nails and look for characteristic signs of onychomycosis.
A doctor may also require nail clippings or scrapings to test for onychomycosis. Tests may involve a fungal culture test.
Tips to prevent these infections include:
The American Academy of Dermatology Association (AAD) recommend the following to prevent tinea pedis or athlete’s foot:
- wearing sandals or footwear (that do not obstruct the entire foot) in public areas
- keeping the feet dry
- washing and drying the feet every day
- wearing socks made of natural fabrics
- alternating the shoes worn every day
- not sharing clothing or shoes with other people
The AAD recommends the following preventative measures:
- wearing sandals or flip-flops when the weather is warm
- wearing a clean pair of socks every day
- alternating shoes every day if possible
- keeping the nails short by trimming them
- sanitizing nail clippers before use
- keeping feet dry and clean
- moisturizing skin around the nails and feet regularly
Treatment options for both infections may include:
Measures to treat tinea pedis include wearing more appropriate footwear and ensuring regular washing and drying of the feet.
A doctor may prescribe topical antifungal medication, such as miconazole cream, to treat the tinea pedis more effectively. A person can apply these creams directly to the affected skin once or twice a day.
Typically, it takes 2–4 weeks for the cream to work, but it may work more quickly if the infection is mild.
At-home remedies for onychomycosis include washing the skin around the nail regularly and keeping the feet clean and dry.
An older study found that treating onychomycosis with mentholated ointments, such as Vicks VapoRub, showed a positive effect in 83% of participants. Some people also think that tea tree oil helps treat nail fungus. However, research is limited.
Topical antifungal creams for mild infections include amorolfine and ciclopirox. The number of times a person will need to apply the treatment will depend on the medication.
The AAD state that antifungal pills have a higher cure rate than topical creams. They also work more quickly, so a person may only need to take them for a few months.
The doctor may recommend removal of the nail if the infection is severe. A doctor can do this surgically or chemically. With both treatment options, the nail can grow back.
Recently, scientists have experimented with the use of lasers to treat onychomycosis. Although specialists indicate that the procedure is safe, it can cause some pain and bleeding.
A person should see a doctor if they notice any changes to the skin or nails of the feet, including:
- color changes
- changes to the texture
A person should also seek medical advice if they have tried at-home remedies and the condition persists.
Fungal infections such as tinea pedis and onychomycosis are widespread. Hot and humid environments and restrictive footwear encourage fungal infections.
A person should follow the recommended preventive measures to reduce the risk of infection.
If a person notices changes to the skin or nails of the feet, they should seek the advice of a medical professional to ensure early antifungal treatment.