Fungal Skin Infections

What are fungal skin infections?

Fungal skin infections are very common. They are caused by two main groups of organisms: dermatophytes, which cause tinea or ringworm, and yeasts, such as Candida and Malassezia. Despite the name, ringworm has nothing to do with worms.

Who gets them?

Fungal infections thrive in warm, moist conditions. Risk factors include sweating, tight or non-breathable clothing and footwear, using shared showers and changing rooms, contact sports, diabetes, being overweight, a weakened immune system, and recent antibiotics (for yeast infections). Some types of ringworm are caught from pets or farm animals.

What causes them?

Fungal skin infections are caused by dermatophyte fungi or by yeasts. These organisms thrive in warm, moist conditions, so infections are more likely in skin folds, on the feet and where sweat is trapped by clothing or footwear.

Are they hereditary or contagious?

Fungal skin infections are not inherited.

Dermatophyte infections can spread from person to person, from animals, and from contaminated surfaces such as floors, towels and hairbrushes. They can also spread from one part of your own body to another, for example from the feet to the groin. Yeast infections are usually caused by organisms that already live on the skin and are not typically passed between people.

What do they look and feel like?

Fungal infections can look different depending on the type of organism and where on the body they occur.

Dermatophyte infections (tinea)

Athlete's foot (tinea pedis) causes itchy, peeling, cracked or soggy skin between the toes, or dry scaling across the sole and sides of the foot, sometimes with small blisters.

In the groin (tinea cruris), an itchy red or brown rash with a raised, scaly border spreads over the groin and inner thighs. It is more common in men.

Body ringworm (tinea corporis) causes one or more ring-shaped, itchy patches with a scaly, raised border that spreads outwards, often with clearer skin in the centre.

Scalp ringworm (tinea capitis) causes scaly patches with broken hairs and hair loss and is most common in children.

Fungal infection can also affect the hands, face, beard area and nails.

Yeast infections

Candida (thrush) commonly affects warm, moist skin folds such as the groin, under the breasts, the armpits and between the fingers. It causes a red, moist, sore rash, often with small satellite spots around the edge. It can also affect the genitals and the corners of the mouth.

Pityriasis versicolor is caused by Malassezia yeast, which normally lives on the skin. Flat, finely scaly patches develop on the trunk, shoulders and upper arms, and these can be paler or darker than the skin around them. It is often more noticeable after a tan, because the affected skin does not darken in the same way. It is more common in young adults and in hot, humid conditions.

How are they diagnosed?

Fungal infections can often be recognised from their appearance, but several conditions, including eczema and psoriasis, can look similar. Skin scrapings, hair samples or nail clippings are often sent to the laboratory to confirm the diagnosis and identify the type of fungus.

Steroid creams and fungal infections

Using steroid creams on a fungal infection, which is easily done if it is mistaken for eczema, can reduce the redness and itch temporarily but allows the fungus to spread. This changes the appearance of the rash, making it harder to recognise. This is called tinea incognito.

What are the treatment options?

Dr Mounsey will confirm the diagnosis, often with skin scrapings sent for testing, as several skin conditions can look like fungal infection. Most infections respond well to antifungal creams such as terbinafine or clotrimazole, or antifungal shampoos for pityriasis versicolor. Widespread infections, scalp infections and infections that keep returning may need antifungal tablets. He will also advise on reducing the chance of the infection coming back, such as keeping the skin dry and treating athlete's foot.

What is the outlook?

Most fungal skin infections clear well with appropriate treatment, although they can come back, particularly if the underlying conditions that encourage them persist.

More information

British Association of Dermatologists patient leaflet on pityriasis versicolor: https://www.bad.org.uk/pils/pityriasis-versicolor

British Association of Dermatologists patient leaflet on tinea capitis: https://www.bad.org.uk/pils/tinea-capitis

This page gives general information only and is not a substitute for a consultation. Everyone's skin is different, and what is right for you will depend on your own circumstances. If you are worried about a skin problem, please book an appointment with Dr Mounsey or speak to your GP. If you have a mole or skin lesion that is changing, bleeding or growing quickly, please seek medical advice promptly.