Athlete's foot
What is athlete's foot?
Athlete's foot, or tinea pedis, is a common fungal infection of the foot caused by a group of fungi called dermatophytes (also known as ringworm) that colonize the skin. It is a contagious condition that can be spread by direct or indirect contact with the infected skin.
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Fungal infection
Any inflammatory condition caused by a fungus, a certain type of microscopic organism that includes yeasts, molds and mushrooms.
Causes
Athlete's foot is caused by a group of fungi called dermatophytes. They use keratin, a component of skin, as an energy source. The severity of your response depends on the species and strain of dermatophyte causing the infection.
Microscopic illustration of Epidermophyton floccosum, a type of dermatophyte.
Risk factors
Risk factors for athlete's foot include:
- Damp, humid conditions, such as wearing damp socks;
- Walking barefoot in public areas such as locker rooms and communal showers or pools;
- Close contact with an infected person or animal;
- Sweaty feet confined in tight shoes, and;
- Having a weakened immune system.
Signs and symptoms
In athlete's foot, itchy blisters containing a clear fluid appear, usually between the toes. Other presentations of athlete's foot include:
- Pustules or blisters on the sides of the feet (caused by Tinea interdigitale);
- Ringworm-like patches on the top of the foot;
- Dry, patchy scales on the sole of the foot (chronic hyperkeratotic tinea), and;
- Dry, patchy scales on the whole of the sole, heel and sides of the foot (extensive hyperkeratotic tinea, usually caused by Tinea rubrum).
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Pustules
A small skin blister that contains pus.
Methods for diagnosis
Potassium hydroxide exam
A scraping of your skin from the affected area is added to potassium hydroxide (KOH) and examined under a microscope. KOH destroys non-fungal cells, making it easier to see if any fungal cells are present.
Skin biopsy
A skin biopsy is performed only when other skin infections have to be ruled out.
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Skin biopsy
A diagnostic procedure in which a sample of skin is removed and tested for abnormalities including cancer and infection.
Types of treatment
Athlete's foot is treated with antifungal creams such as ketoconazole and terbinafine that are applied directly to the affected area. Oral antifungal medications such as fluconazole are used for infections that do not respond well to topical cream. Treatment for some time after symptoms have subsided is needed to prevent the tinea's return.
Athlete's foot can be treated with a topical antifungal cream.
Potential complications
Antifungal side effects
Oral antifungal medications can cause nausea and liver damage if used for a prolonged period of time. Antifungals applied to the skin can cause itching and a burning sensation.
Contagion
Tinea spreads easily to other parts of the body. It can also result in breaks in the skin that cause permanent scarring, or lead to bacterial infections.
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Antifungals
A medication that kills fungi or inhibits their growth.
Prognosis
Although athlete's foot can usually be cured, it is common for it to come back. If athlete's foot keeps recurring, it is possible the fungus is present on another part of your body that you have not been treating, particularly under the nails.
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Fungus
An organism from the fungi kingdom, which is a separate group to plants or animals, and includes yeasts, molds and mushrooms. Fungi feed on organic matter.
Prevention
Maintaining good hygiene by washing and drying properly, washing linen and towels in hot water and not sharing them with others can help prevent the spread of athlete's foot. You can reduce your risk of infection, and infection of others, by not walking barefoot in public showers or spaces such as gyms and pools.
References
- Antifungal Medicines - Side effects - NHS Choices. Accessed 16 September 2014 from link here
- Clinical epidemiological and therapeutic profile of dermatophytosis. Accessed 16 September 2014 from link here
- Dermatophyte (tinea) infections. Accessed 16 September 2014 from link here
- Diagnosis and Management of Common Tinea Infections - American Family Physician. Accessed 16 September 2014 from link here
- Epidemiology of dermatophytoses: retrospective... [New Microbiol. 2012] - PubMed - NCBI. Accessed 16 September 2014 from link here
- Johns Hopkins Guides: Tinea pedis. Accessed 16 September 2014 from link here
- Mycology Online | Dermatophytosis. Accessed 16 September 2014 from link here
- Revista da Associação Médica Brasileira - Efficacy of topical antifungal drugs in different dermatomycoses: a systematic review with meta-analysis. Accessed 16 September 2014 from link here
- Sao Paulo Medical Journal - Oral treatments for fungal infections of the skin of the foot. Accessed 16 September 2014 from link here
10 Most frequently asked questions (FAQs)
Tinea pedis is a contagious fungal infection of the foot, known commonly as athlete's foot . It usually begins with itchy, fluid-filled blisters between the toes and is spread by direct or indirect contact with the skin. However, it can also present as dry, scaly patches on the sole and heel of the foot, or blisters on the side of the feet. What are the symptoms of tinea pedis? Symptoms of tinea pedis are itchy blisters that contain a clear fluid, which most commonly occur between the toes. Other types of tinea pedis include pustules on the side of the feet (caused by tinea interdigital), and scaly, dry patches on the sole, heel and side of the feet. Tinea pedis is caused by a group of fungi called dermatophytes (also known as ringworm). Dermatophytes use keratin, a component of the skin, as an energy source. Depending on the species and strain of dermatophyte causing infection, the severity of your response will vary. How is tinea pedis diagnosed? A skin scraping from the affected area is added to potassium hydroxide (KOH). KOH destroys fungal cells, which makes it easier to see if any fungal cells are present under a microscope. How is tinea pedis treated? Tinea pedis is treated with topical antifungal creams such as ketoconazole and terbinafine, applied directly to the affected area, or oral antifungal medications such as fluconazole. Treatment for a while after symptoms have disappeared is needed to prevent it returning. Although anyone can get tinea pedis, it is more common in males in their late teens and early adulthood. Can tinea pedis be prevented? You can reduce your risk of getting it, or sharing it if you already have it, by not walking barefoot in public showers or spaces such as gyms and pools.
Related topics
Tinea, also known as ringworm, is a common skin infection with a characteristic ring-like appearance. It is caused by several types of fungus and can appear on different parts of the body including the scalp, chest, feet, groin, face, hands and nails. Tinea is very contagious but easily treated. Contact dermatitis is inflammation of the skin caused by direct contact with an irritant or something that induces an allergic reaction. It commonly presents as a red, itchy skin rash usually on the hands or face. Avoiding the cause once identified can prevent it happening it the future. Folliculitis describes the inflammation of the hair follicles in the skin. Folliculitis can occur anywhere on the body where hair grows, but is most common around legs, armpits, buttocks, face, scalp and groin. It causes red bumps, pimples, crusting and itchy or painful skin. It usually settles within a few weeks. Hives is a skin rash characterised by itchy, red swellings. It can appear on the face, trunk, arms, legs, and lips. Hives are commonly a sign of an allergic reaction, which can be triggered by a range of factors. Depending on the duration and severity, different treatment options are available.