Most commonly known as "athlete’s foot fungus", Tinea Pedis is the term used for a dermatophyte infection of the bottom of the feet and in between the toes.
Tinea pedis is thought to be the world's most common dermatophytosis. Reportedly, 70% of the population will be infected with tinea pedis at some time. This occurs more often in men than women and is usually seen after puberty. (Yes, stinky teenage boys are the most common!) Childhood tinea pedis is rare before adolescence but can occur.
Commonly, patients describe itchy, scaly soles and, often, painful fissures between the toes. Less often, patients describe pustules or ulcers associated with the rash. Elderly patients often attribute their scaly feet with dry skin.
A simple fungal infection such as athlete's foot can become "super-infected" with bacteria. If this should happen, the rash will become increasingly painful and red. Your foot may become swollen, and you may develop blisters and even open sores in the infected area. These are indications that you may need oral antibiotics and will need to call your podiatrist.
It is unlikely that athlete's foot would ever become severe enough that a trip to a hospital's emergency department is required. However, if you have diabetes or any other type of illness that will make it hard for your body to fight off an infection, athlete's foot may become an emergency.
If you develop severe pain, redness, or swelling, notice a puslike drainage, see large blisters or ulcers on your foot, or if you develop a fever, you should be seen as soon as possible by your podiatrist, who may direct you to a hospital for IV antibiotics.
Tinea pedis is seen most commonly in four different forms:
- Interdigital
- This is between the toes and is usually red or whitish, wet-looking skin with fissuring and scaling. This is most common between the 4th and 5th toes and is very itchy. This type can also lead to a bacterial super-infection, which can be dangerous.
- Chronic Hyperkeratotic
- This type is characterized by painful, blister-like lesions or pimples on the bottom of your feet. They can either have clear or pus-like fluid and accompanied by redness and scaling. A bacterial super-infection that can lead to cellulites is a complication of this type.
- Vesicular
- This type is characterized by painful, blister-like lesions or pimples on the bottom of your feet. They can either have clear or pus-like fluid and accompanied by redness and scaling. A bacterial super-infection that can lead to cellulites is a complication of this type.
- Ulcerative
- The ulcerative type is characterized by pustular eruptions that become ulcers and erosions, especially in between the toes and extending on to the soles of your feet. This is often accompanied by cellulites and skin slough of large areas. This is usually seen in diabetics and immuno-compromised patients.
What causes tinea pedis?
Texas! Seriously, a hot, humid, tropical environment and prolonged use of closed in shoes; with the resulting sweaty feet, are risk factors for all types of tinea pedis. Certain activities like swimming and constant sweating in sports cleats/shoegear may also increase the risk of tinea pedis. (Again, sweaty adolescent boys!) It is more common in some families, but no certain genetic marker has been identified.
How does this happen?
Infection can occur through contact with infected scales on a bath, pool or gym floor. Closed in shoes promote the growth of the fungus in a most, warm dark environment; so wearing other peoples shoes can also spread the infection.
How is tinea pedis diagnosed?
Certain lab tests, called a KOH or PAS stain, can identify the fungus from skin scrapings or the roof of the vesicles. In some cases a fungal culture is needed to identify the particular fungus.
How is tinea pedis treated?
Tinea pedis can be treated with topical or oral antifungals or a combination of both in severe or recurrent cases. Topical agents are used for 2-6 weeks. Orals may be needed for up to a month for skin infections and 4 month for combination infections including toenails. A patient with chronic hyperkeratotic (moccasin) tinea pedis should be instructed to apply medication to the bottoms and sides of his or her feet. For interdigital tinea pedis, even though symptoms may not be present, a patient should apply the topical agent to the interdigital areas and to the soles because of the likelihood of plantar-surface infection.
Recurrence of the infection is often due to a patient's stopping the medication after symptoms go away. The patient should be educated to motivate them to continue use until the entire tube of topical anti-fungal is empty.
Moccasin-type tinea pedis is often resistant to topical antifungals alone, owing to the thickness of the scale on the plantar surface. Combination therapy using topical urea or other keratolytic, exfoliating cream with topical antifungals should improve the response to topical agents. However, patients with extensive chronic hyperkeratotic tinea pedis or inflammatory/vesicular tinea pedis usually require oral therapy, as do patients with concomitant onychomycosis, diabetes, peripheral vascular disease, or immunocompromising conditions.
Tips for preventing tinea pedis:
- It is important to keep your feet clean and dry. Wear clean absorbent socks made of natural fibers or wicking fibers, such as cotton or cotton-poly blends like Coolmaxx and change them during the day if your feet become moist or sweaty.
- If possible, remove the insoles of shoes and sneakers to allow them to dry out over night. Alternatively, spray them with Mycomist spray and dry them with a hair dryer.
- Dusting the inside of your shoes and socks with talcum powder or a medicated powder will help to decrease the moisture level.
- Alternate wearing different pairs of shoes to allow them to dry out for a day or two at a time. (Or leave them outside overnight when it’s 100 degrees!)
- Wear sandals or Crocs in public locker rooms and swimming areas.
- Do not wear someone else's shoes, especially if that person has athlete's foot.
- Thoroughly clean home showers and floors where family members walk barefooted to avoid spreading the fungus. (or just don’t walk barefoot!)
If you think you have the symptoms of tinea pedis, try an over-the-counter anti-fungal for 1-2 weeks, as long as you don’t also have redness streaking up your foot; but if this does not stop the itching rash, call or contact the office for an appointment. Remember that tinea pedis is often super-infected with bacteria and can lead to cellulitis which requires IV antibiotics in the hospital!