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What is ringworm?

Ringworm is a fungal skin infection caused by parasites that live on dead skin tissue. (It is not due to a worm as its name implies!) There are many types of fungal germs (fungi) and some can infect the skin, nails, and hair.

Fungal infections are also known as 'jock itch', 'tinea', 'tinea infections', 'dermatophyte infections' or 'dermatophytosis'. This leaflet just deals with ringworm of the skin (sometimes called tinea corporis).

Veja também os folhetos separados chamados Fungal Scalp Infection (Scalp Ringworm), Athlete's Foot (Tinea Pedis), Fungal Groin Infection (Tinea Cruris) e Fungal Nail Infections (Tinea Unguium).

How do you get ringworm?

Generally speaking, ringworm and other fungal skin infections are contagious, but not especially so. It is possible to touch someone's skin if they've got ringworm or some other fungal infection and, as long as hands are washed afterwards, it's unlikely that it will be passed on.

Occasionally ringworm can be caught by the following means:

• From person to person by touching a person who has the infection.

• From touching items which have been in contact with an infected person, for example, towels, clothes, bed linen or chairs which have been used by somebody who has ringworm.

• From animals. Some animals, such as dogs, cats, guinea pigs and cattle, have fungal infections on their skin. They can pass on the infection, especially to children. (Animals can be treated too. If it is suspected that a pet is the cause, advice should be sought from a vet.) Farm animals can also be a source. Touching a farm gate where infected animals pass through may be enough to infect skin.

• From soil. Rarely, fungi can be present in soil and the infection can be caught from contact with the soil.

What does ringworm look like?

Tinea corporis

© Corina G., Public domain, via Wikimedia Commons

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Ringworm symptoms

The most common symptom of ringworm is the emergence of a small area of infected skin that tends to spread outwards. In most cases, ringworm develops into a rounded, red, inflamed patch of skin.

The outer edge is more inflamed and scaly than the paler centre. So, it often looks like a ring that becomes gradually larger - hence the name ringworm. Sometimes only one patch of infection occurs. Sometimes several patches of ringworm occur over different parts of the body.

The rash may be irritating, itchy and inflamed. If it's not itchy and annoying, it's very unlikely the ringworm is fungal.

Sometimes fungal skin infections and symptoms of ringworm look similar to other skin rashes, such as psoriasis, discoid eczema or granuloma annulare.

Ringworm treatment

Antifungal creams for ringworm

Uma creme antifúngico can be bought from pharmacies over the counter (OTC) or prescribed. There are various types and brands, which include terbinafina, clotrimazol, econazol, cetoconazol e miconazol. These are good at clearing fungal skin infections such as ringworm. There is no evidence that any one cream is better than any other one.

The cream should be applied to the affected areas for as long as advised. This varies between the different creams, so the instructions should be read carefully. Typically:

• Clotrimazole: apply 2-3 times a day for at least four weeks.

• Miconazole: apply twice a day and continue for 10 days after the skin is back to normal.

• Econazole: apply twice a day until the skin is back to normal.

• Ketoconazole: apply once or twice a day and continue for a few days after the skin is back to normal. Cannot be used for children.

• Terbinafine: apply once or twice a day for one to two weeks. Cannot be used for children.

Antifungal steroid cream

For ringworm skin that is particularly inflamed, a doctor may prescribe an antifungal cream combined with a mild steroid cream. This would normally be used for no more than seven days and an antifungal cream might need to be used alone for a time afterwards.

The steroid reduces inflammation and may ease itch and redness quickly. However, the steroid does not kill the fungus and so a steroid cream alone should not be used; in fact, it will probably make the fungal infection worse.

Antifungal tablets for ringworm

An antifungal medicine taken by mouth is sometimes prescribed if the ringworm infection is widespread or severe. These include terbinafine, griseofulvin, ou itraconazol tablets.

Not all ringworm treatments are suitable for everyone. People who may not be able take antifungal tablets include:

• Women who are pregnant or breastfeeding.

• People with certain liver diseases.

• People at risk of heart failure.

• People with long-standing lung disease.

• Pessoas idosas.

• People taking other medication which may interact with antifungal tablets.

• Crianças.

Antifungal creams and tablets are covered in more detail in the separate leaflet called Antifungal Medicines.

Fatores de risco

Close contact with an infected person or animal is the biggest risk factor. Ringworm is also more common in people living in a warm climate.

General advice and tips for ringworm

Keep the affected area clean and dry.

Do not share clothes or towels. Wash towels, sheets and clothes frequently. Clean the shower or bath well after use. Try not to scratch the rash, as this may spread the fungus to other areas of the body.

There is no need to stay off work or school once ringworm treatment has started.

Is is necessary to contact a doctor for ringworm?

Generally, no. A pharmacist can diagnose ringworm, so they should be consulted first and they will tell you whether or not GP advice is needed.

Advice from a GP should be sought if the ringworm has not improved after using the antifungal medicine prescribed by the pharmacist or in someone with a weakened immune system from other medications or treatments.

How to prevent ringworm

Avoid contact with infected people or animals. Avoid sharing towels, flannels or bedding.