Tinea
What is tinea?
Tinea refers to a group of fungal skin infections that includes athlete's foot, jock itch and 'ringworm' (which is not due to a worm, but rather a fungus that causes ring-shaped rashes). It can occur anywhere on the body, but most commonly affects the feet, scalp and fingernails. Its appearance depends on what type of tinea it is (see 'Types' below).
Causes
Tinea is caused by a group of fungi called dermatophytes that live on the outer layer of skin. They use a component of skin, called keratin, as an energy source. The severity of your symptoms usually depends on the species and strain of fungus that is causing the infection.
Tinea is contagious and can be spread through direct contact with an infected person, or through contact with contaminated objects or surfaces, such as towels, shoes or communal showers.
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Keratin
A fibrous protein that forms hair and nails.
Risk factors
Some factors that can increase the chance of developing tinea include:
- Damp, humid, crowded conditions;
- Close contact with an infected person;
- Sweating excessively;
- Sharing clothing, towels or linen;
- Wearing tight clothing, and;
- Having a weak immune system or certain underlying medical conditions, such as type 2 diabetes.
Types
Tinea corporis
Tinea corporis affects the skin on the body, and is commonly called ringworm. It commonly appears as ring-shaped, red rashes, which are also itchy.
Tinea pedis
Tinea pedis affects the foot, and is commonly known as athlete's foot. It can cause itchy blisters between the toes and on the side on the foot, and dry, scaly patches on the sides and sole of the foot
Tinea cruris
Tinea cruris affects the groin, and is commonly known as jock itch. It causes a red, itchy, raised rash in the groin that can also spread down the inner thighs.
Tinea capitis
Tinea capitis affects the scalp and results in small lumps of raised skin that then flake off and can cause temporary baldness.
Tinea unguium
Tinea unguium affects the nails on the toes and fingers, and is otherwise known as onychomycosis. It causes the nails to gradually thicken and become discolored. Over time they can become brittle and eventually disintegrate.
Methods for diagnosis
Tinea can be diagnosed by an examination of your skin or nails. A scraping of skin or clipping of nail from the affected area can also be sent for testing to confirm the diagnosis. The following tests can be performed on these samples:
Potassium hydroxide exam
The sample is added to potassium hydroxide (KOH) and examined under a microscope. Potassium hydroxide destroys non-fungal cells, making it easier to see if any fungal cells are present.
Fungal culture
If fungus is present on the skin, it can be cultured using a special gel (agar) plate that selectively grows it. Fungi can two weeks or more to grow. The benefit of fungal cultures is that it can also determine the most effective treatment option.
Types of treatment
Tinea is usually treated with topical antifungal creams, such as ketoconazole and terbinafine, which are applied directly to the affected area. Sometimes an oral antifungal medication, such as oral terbinafine or fluconazole, can be prescribed for infections that do not respond well to topical cream. Continuing treatment is usually needed, even after an infection has cleared, to prevent it from returning. It is also important to treat all sites with the fungal skin infection simultaneously, to prevent re-infection in the future.
Prognosis
Although tinea can usually be cured, it is common for it to return. Tinea spreads easily to other parts of the body. Severe cases can sometimes result in breaks in the skin that can cause permanent scarring or a bacterial infection.
Prevention
Maintaining good hygiene by washing and drying the skin properly, washing linen and towels in hot water and not sharing them with others can help prevent the spread of tinea. You can also reduce your risk of getting tinea on your feet by not walking barefoot in public spaces such as showers, gymnasiums and swimming pools.
References
- Antifungal Medicines - Side effects - NHS Choices. Accessed 16 September 2014 from link here
- Dermatophyte (tinea) infections. 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
- Tinea (Ringworm) - Queensland Health. Accessed 16 September 2014 from link here
10 Most frequently asked questions (FAQs)
Tinea is a group of fungal skin infections, such as athlete's foot, jock itch and 'ringworm', which cause characteristic ring-shaped red rashes. A group of fungi called dermatophytes causes tinea. These fungi use keratin, a component of skin, as their energy source. How severely you respond to infection depends on the species and strain of the dermatophyte. Tinea is commonly diagnosed by examining the skin. However, skin scrapings or nail clippings of the affected area can be tested using potassium hydroxide (KOH) or cultured to confirm the diagnosis. Are there different types of tinea? Different types of tinea affect different parts of the body. Ringworm most commonly affects the skin on the body (tinea corporis), the scalp (tinea capitis), the feet (tinea pedis, also known as athlete's foot) or the groin (tinea cruris, also called jock itch), but can also affect the beard area of the face and neck (tinea barbae), other areas of the face (tinea faciei), the hands (tinea manus), and even the nails of the hands and feet (tinea unguium). Tinea can be treated with topical and oral antifungal agents. Tinea is very contagious and can easily be spread through direct contact with an infected person, or through contact with contaminated objects or surfaces, such as towels, shoes or communal showers. You can help prevent the spread of tinea by practicing good hygiene, ensuring linen and towels are washed in hot water and not sharing them with others.
Related topics
Athlete's foot (Tinea) is a fungal infection that causes itchy blisters which usually occur between the toes. Treatment options, such as antifungal creams, can improve symptoms within a few weeks. Jock itch refers to an uncomfortable itch experienced in the groin. It is a common condition caused by a fungal infection, known as tinea. It is treated using antifungal creams and can be prevented by reducing moisture build-up in the groin. 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.