Fungal skin infections: types, treatment and when to see a GP

Fungi are microscopic organisms found in soil, on animals and on human skin. Some types feed on keratin, the protein in skin, hair and nails, and can cause rashes. The NHS lists the common fungal infections by area: nails (fungal nail infection), feet (athlete's foot) and body or scalp (ringworm). Pityriasis versicolor, caused by a yeast-like fungus that lives on normal skin, is another.

Most are superficial and affect only the outer layers of skin. They are rarely dangerous in healthy people but can be persistent and irritating, and they can spread between people, from pets and from damp shared surfaces.

Ringworm produces a rash that, according to the NHS, may look red or darker than the surrounding skin and may be scaly, dry, swollen or itchy. It is usually ring-shaped but can look different on the face, neck or scalp, and can appear anywhere including the scalp (tinea capitis) and groin (jock itch). On brown and black skin the colour of the rash may be less noticeable. On the scalp it may cause patchy hair loss.

Athlete's foot typically causes itchy white patches between the toes, sore and flaky patches on the feet, and sometimes cracked or bleeding skin or fluid-filled blisters. The NHS says that if it is not treated it can spread to the toenails and cause a fungal nail infection.

Pityriasis versicolor causes flat, round patches that are pink, red or pale brown on white skin and paler than the surrounding skin on brown or black skin. They usually appear on the chest, upper back, upper arms, neck or tummy, may feel scaly or itchy, and may not tan in the sun. The NHS notes that it is not caused by poor washing and cannot spread from person to person.

For ringworm and athlete's foot, the NHS recommends speaking to a pharmacist first. For ringworm, a pharmacist can look at the rash and recommend an antifungal tablet, cream, gel or spray, which may need to be used every day for up to 4 weeks. For athlete's foot, creams, sprays and powders are available and usually take a few weeks to work, and you may need to try a few to find one that works.

For pityriasis versicolor, the NHS says treatments are antifungal shampoo such as ketoconazole, applied to the affected skin and rinsed off after 10 to 15 minutes, or antifungal cream. A GP may prescribe tablets if the area is large or other treatments fail. It can take a few months for skin colour to return to normal and the patches can come back, in which case a GP may suggest long-term treatment such as using antifungal shampoo every few weeks.

Complete the full course even if the rash seems to have cleared, as the NHS advises. A GP may take a skin scraping for laboratory testing, prescribe a steroid cream alongside antifungal cream, or prescribe antifungal tablets for several weeks, and may refer to a dermatologist if needed.

The NHS advice for athlete's foot is to keep feet clean and dry, dab between the toes after washing, use a separate towel for the feet, wear clean cotton socks every day, wear flip-flops in changing rooms and showers, and avoid sharing towels, socks or shoes or wearing the same pair of shoes for more than 2 to 3 days in a row. Treatment should continue after the rash clears to stop it coming back.

For ringworm the NHS says to start treatment as soon as possible, wash towels and bedsheets regularly, wash hands after touching animals or soil, avoid sharing towels, combs or bedsheets and avoid scratching, which could spread it. It says to take pets to the vet if they might have ringworm, for example if they have patches of missing fur. A child can go to school or nursery once treatment has started.

The NHS advises seeing a GP if ringworm has not improved after antifungal medicine recommended by a pharmacist, if it is on the scalp (which usually needs prescription tablets and shampoo), or if you have a weakened immune system, for example from chemotherapy, steroids or diabetes.

For athlete's foot, see a GP if pharmacy treatment does not work, you are in a lot of pain, the foot or leg is hot, painful and red (which could be a more serious infection), the infection spreads to your hands or other areas, or you have diabetes or a weakened immune system. If skin patches have changed colour, the NHS says to see a GP or pharmacist, as pityriasis versicolor will usually only go away if treated, and other conditions such as vitiligo or psoriasis can look similar.

Most fungal skin infections are managed through community pharmacies, which the NHS highlights, with GP review if needed. Dermatology referral is reserved for uncertain or resistant cases. Private dermatology appointments are an option for those who prefer quicker specialist review, but the first-line treatments are generally the same.