Fungal skin infections

Published by Bupa's Health Information Team, March 2010.

This factsheet is for people who have a fungal skin infection, or who would like information about them.

Fungal skin infections are infections on the skin caused by a fungus. Certain types of fungus, or excessive growth of normally harmless types, cause the symptoms of a fungal skin infection. Most fungal skin infections can be treated effectively.

About fungal skin infections

Fungal skin infections usually affect your skin because they live off keratin, a protein that makes up your skin, hair and nails.

Fungal skin infections are divided into groups, depending on what type of organism is involved. The full name depends on where the infection is found on your body.

Types of fungal skin infections

Some common fungal skin infections are listed below.

Dermatophyte infections

Most basic fungal skin infections are caused by dermatophytes - types of fungi that cause skin, nail and hair infections. They are very common, affecting between one and two in 10 people at some point in their lives. Dermatophyte infections include the following.

Athlete's foot (Tinea pedis and Tinea manuum)
Around 25 in 100 adults have athlete's foot at some time in their lives. It's caused by a combination of fungi and bacteria, causing your skin to become itchy, dry, scaly and red, especially between your toes. Sometimes it causes blisters and cracked skin. You often pick up athlete's foot from contaminated skin scales in swimming pools, showers and saunas. If you don't wash your hands after touching a contaminated area, it can spread to your hands where it's known as Tinea manuum. It mostly affects the creases on your palms and sides of your fingers.

Nail infections
Onychomycosis is the name for any fungal nail infection. Tinea unguium (ringworm of your nails) is a common infection. Your nails become malformed, thickened and crumbly. Not all nails affected like this are caused by fungal infections, but it's a common cause. Toenail infections are commonly linked with athlete's foot. Your fingernails can be affected too.

Ringworm of the groin (Tinea cruris)
This is often called 'jock itch' because it occurs in sportspeople and is common among young men. It causes an itchy, red rash in your groin and the surrounding area and is usually seen in men who have been sweating a lot. Often you will also have athlete's foot, and scratching your feet, followed by your groin may spread the infection.

Ringworm on the body (Tinea corporis)
This often affects exposed areas of your body, such as your abdomen (tummy) or your limbs, causing red raised or flat patches and rings that can merge, grow and spread. The rings are scaly at the edge with clear skin at the centre. The patches spread out from the centre. Ringworm can be caught from domestic animals.

Ringworm of the scalp (Tinea capitis)
This usually affects young children, especially those living in urban areas and who are of African-Caribbean origin. It spreads from person to person, causing hair loss and inflammation of the affected area. You can be infected by this fungus without developing any symptoms, but become a carrier, spreading the infection to others, sometimes for years.

Yeast infections

Other fungal skin infections are caused by yeast infections. Yeast infections include the following.

Intertrigo
Intertrigo is a yeast infection of skin folds caused by the fungus Candida albicans, which lives on your skin and in your digestive system. It affects areas where skin touches skin, such as your armpits, groin, and under heavy breasts or fat folds, where the environment is warm and moist. It can cause itching, soreness, spots and scales, creating a white-yellow curd over the infected area.

Pityriasis versicolor
This yeast infection causes dark patches to form on pale or untanned skin and light patches on tanned or darker skin. Another name for this condition is Tinea versicolor (versicolor means 'of various colours'). Teenagers and young adults are most often affected in the UK.

Thrush (Candida albicans)
The fungus Candida albicans usually lives in harmony with us and rarely causes problems. However, in certain situations, such as if you're ill, have poorly controlled diabetes, are pregnant or using antibiotics, the fungi multiply and cause thrush symptoms.

Thrush can affect your mouth and tongue, areas lined with a mucus membrane such as your vagina, and other moist, folded skin. Thrush infection often looks like small white patches, which leave a red mark when rubbed off. In adults, vaginal thrush can cause itchiness and a thick, white discharge.

Thrush sometimes affects men, causing a painful red rash on the head of the penis (glans). It also commonly affects newborn babies in the mouth (oral thrush).The white patches may be mistaken for breast or formula milk. It isn't usually serious, but babies with thrush in their throats may stop feeding properly. Babies may also develop thrush in the nappy area.

Symptoms of fungal skin infections

The symptoms and appearance of a fungal skin infection depend on the type of fungus causing it and the part of your body affected.

Fungal skin infections can cause rashes with a variety of different appearances. Some are red, scaly and itchy, whereas others can produce appear similar to dry skin. The fungus may infect just one area or several areas of your body.

Fungal infections of your scalp or beard can lead to hair loss. Fungal rashes can sometimes be confused with other skin conditions, such as psoriasis and eczema.

Causes of fungal skin infections

You're more at risk of getting a fungal skin infection if you:

• have recently taken a course of antibiotics
• are taking steroids
• have diabetes
• are overweight
• have had fungal skin infections in the past
• have a weakened immune system caused, for example, by cancer or HIV/AIDS

Moist skin encourages fungal skin infections. This means you're more likely to pick one up if you don't dry your skin properly after sweating or bathing, or if you wear tight clothes that don't allow sweat to evaporate. Damage to the surface of your skin, such as a cut or graze, can also encourage fungi to grow.

Fungal infections inside your body can cause more serious health problems than those on your skin. These infections only affect people whose immune systems aren't working properly - either as a result of an illness such as HIV/AIDS, or because you're taking medicines that suppress your immune system.

How do fungal skin infections spread?

Fungal skin infections can be spread from person to person. For example, athlete's foot is thought to be spread in communal areas, such as gyms and swimming pools. Contact with bed sheets or towels and personal items such as hairbrushes can also spread fungal infections. It's also possible to catch some fungal infections from animals such as cats or dogs, and, more rarely, cattle. Ringworm is occasionally caught this way.

Diagnosis of fungal skin infections

Your GP will ask about your symptoms and examine you. He or she will look at the appearance and location of your rash. Your GP may also take a skin scraping, or a fragment of your nail or hair, and send it to a laboratory for testing, to confirm the diagnosis.

Treatment of fungal skin infections

As most fungal skin infections are surface infections, you will usually need to use antifungal treatments that are applied directly to your skin in the infected area (topical treatments).

There are a variety of treatments available in the form of creams, lotions and medicated powders. If the rash covers quite a large area of your skin, or affects your nails or scalp, you may need to take some tablets.

Some treatments are available over-the-counter from a pharmacist, without a prescription. For example, sprays are available for treating athlete's foot. Ask your pharmacist for advice.

Stronger forms of topical treatments and antifungal medicines in tablet form are only available if you have a prescription from your GP. You may be prescribed antifungal shampoo if you have a scalp infection.

These treatments are usually effective. They can occasionally cause side-effects, which may include skin irritation or an upset stomach. It isn't unusual for your rash to return, even when it seems to have been treated. You may need to take some treatments for a few weeks, or up to 18 months for toenail infections.

If you're buying an over-the-counter antifungal treatment, you need to be sure that you have a fungal infection. You may recognise the rash from a previously diagnosed fungal infection. But if there is any doubt about your diagnosis, or if over-the-counter treatments don't work, contact your GP.

Prevention of fungal skin infections

There are some steps you can take to reduce your risk of getting a fungal skin infection. You should:

• dry your skin carefully after bathing
• wear loose fitting clothes and underwear
• choose cotton socks and natural fibre underwear to allow your skin to breathe
• not share towels, hair brushes, and combs
• wash bed linen and clothes often to get rid of fungal spores
• throw away or disinfect pillows, hats, combs or scissors with bleach if someone in your family has scalp ringworm
• always wear flip-flops or plastic shoes in communal area such as swimming pools
• alternate shoes every two or three days so that they have time to dry out (to help prevent athlete's foot)
• wear synthetic fibres that 'wick' the sweat away from the body, helping to keep your skin dry, if you're exercising

If you have diabetes, you need to keep your blood sugar levels under control (for more information, see Related topics).

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.