Definition
Ringworm is a fungal infection affecting either the surface skin (tinea corporis), the feet (tinea pedis) or the scalp (tinea capitis). The fungus thrives on dead skin cells and therefore affects the surface layer of the skin. If untreated and with certain species of fungus, deeper infections can occur (kerion).

Incidence, Age and Sex
Most fungal infections affecting the scalp (tinea capitis) affect children. Adults produce grease (sebum) which discourages fungus from growing in the scalp. Fungal scalp infections are therefore exceedingly rare unless there is a more unusual fungal infection such as cat or ringworm. Tinea pedis is commoner in adolescents and adults. Males are more commonly affected than females. Tinea corporis is commoner in adults than in children.

Causes and Preventions
There are numerous different fungi which can cause fungal skin disease. Athlete’s foot is commonly caused by a fungus known as tinea rubrum. This often causes the typical ringworm appearances on the body (tinea corporis).

Tinea capitis is commonly caused by fungus acquired from domestic pets such as cats and dogs (known as microsporum canis).

Fungus is transmitted by spores which can remain dormant out with the human body and therefore can be transferred by communal changing facilities, or by direct skin contact. Tinea capitis (scalp ringworm) is usually caused by direct scalp contact in the school playground or by contact with an infected domestic pet.

Athlete’s foot (tinea pedis) is caused by a fungus which thrives on heat and moisture. Inadequate drying of toe web spaces is one of the main reasons for fungus to become established.

Signs and Symptoms
Athlete’s foot commonly starts between the 4th and 5th toe web spaces with a dry scaly patch which then becomes soggy with subsequent splitting and cracking. It may then extend to other toe web spaces and occasionally involve the nail plate (see tinea unguium). If splits occur then there is local discomfort. Irritation is the other main symptom.

Ringworm affecting the body (tinea corporis) presents as a scaly ring-like lesion which tends to be itchy. This can occur at any site on the skin. Fungal infections may also occur in the groin where they are called tinea cruris. This is due to the warmth and moisture in this area which favours fungal growth.

When fungal disease affects the scalp (tinea capitis) a small scaly, slightly itchy red patch may develop within the hair bearing skin. This is then associated with a breaking off of the hair shaft resulting in a small bald patch. If untreated this may then extend over a larger area of the scalp or involve multiple areas.

Fig 1.  Athletes foot	Fig 2.  Scalp ringworm

Complications of Disorder
Athlete’s foot (tinea pedis) if untreated may continue to extend over the feet and pose a potential infectious risk to other individuals. Broken down skin of the feet can allow deep-seated infections to occur (cellulitis) which may require hospital treatment.

If ringworm of the scalp (tinea capitis) is not effectively treated permanent scarring and loss of hair follicles may occur resulting in localized bald scarred patches.

There is no spread of fungal skin disease to internal organs of the body.

Tests
The diagnosis can be confirmed by taking scrapings from the surface of the skin and examining them under the microscope for fungal hyphae and or culturing the skin scales for a period of 3 weeks to identify the fungal organism.

Up to one-third of clinically diagnosed athlete’s foot is incorrect, with poor foot hygiene including sogginess and maceration low grade bacterial infections may be confused. Where there is a lack of response of treatment then fungal skin scrapings can help to aid the diagnosis.

Ringworm (tinea corporis) can again be diagnosed by skin scrapings. This condition is often misdiagnosed. Psoriasis, granuloma annulare and other skin conditions may be misdiagnosed as a fungal infection. Where there is doubt in the diagnosis fungal skin scrapings can aid the diagnosis.

Scalp fungal disease (tinea capitis) can again be identified from scrapings taken from the edge of the affected area. Some fungus will fluoresce up a green colour when examined under an ultraviolet Wood’s lamp which is similar to a UV security marking lamp.

Treatment
Athlete’s foot (tinea pedis) requires attention to good foot hygiene. The skin of the toe web spaces should always be adequately dried. Drying powders may aid prevention but rarely help treat the active disease. A local anti-fungal cream applied to the skin of the affected area is the treatment of choice (topical anti-fungal). These include Clotrimazole, Miconazole, Econazole and Sulconazole, some of which are available over the counter without a prescription. In practice these have to be applied for at least 6 to 8 weeks to ensure clearance after 4 weeks and a further 2 weeks of treatment to ensure eradication of any remaining spores.

A newer anti-fungal cream (Terbinafine cream) may only require a 2 week period of treatment for an effective cure to be obtained. However it usually takes at least 4 to 6 weeks for clinical recovery to occur even with this treatment. Its safety for use in children is not clearly established and any potential harmful effects it may cause in pregnancy again are not established. It is also a more expensive preparation.

Ringworm, fungal skin disease (tinea corporis) will respond to the same treatment as athlete’s foot. For more extensive disease an anti-fungal tablet by mouth should be considered. These include Griseofulvin taken for 6 weeks, Terbinafine or Itraconazole taken for 2 weeks. When 2 week courses are used of these drugs it takes approximately 4 to 6 weeks for the drugs to work their way out through the skin for clinical clearance to occur. If drug treatment is used this should be combined with local (topical) application of an anti-fungal cream.

Fungal infections of the scalp (tinea capitis) require a combination of an anti-fungal tablet by mouth and anti-fungal cream applied locally. Griseofulvin has a well established safety profile in children and is still currently the treatment of choice for most fungal scalp disease. The dose is calculated on the weight of the child and has to be taken with either fatty food or a glass of milk to ensure absorption.

When fungal disease affects adult scalps then the other anti-fungal drugs (Terbinafine, Itraconazole) can be considered.

Outcome
If the diagnosis is correct, effective treatment is available for all fungal skin disease.