Ringworm and fungal nail infections explained

What causes ringworm and fungal infections?

Ringworm and related infections are caused by fungi called dermatophytes, which feed on keratin, the material that makes up the outer skin, hair and nails. They thrive in warm, damp places, which is why they often affect the feet, groin and skin folds. The same fungi cause several familiar conditions: ringworm on the body, athlete's foot between the toes, jock itch in the groin, and fungal nail infections. They spread easily through direct skin contact, sharing towels, bedding, shoes or floors such as changing rooms, and from infected pets and farm animals. Anyone can catch them, but warmth, sweating, tight footwear and minor skin damage make infection more likely. They are not a sign of poor hygiene.

Recognising ringworm on the skin

Ringworm on the body typically shows as a red or discoloured, scaly patch that slowly grows outwards, often clearing in the centre to leave a ring shape with a raised, slightly bumpy edge. It is usually itchy. On the feet, athlete's foot causes itchy, flaky, sometimes cracked or soggy skin between the toes; in the groin it produces an itchy rash in the skin folds. On the scalp, ringworm can cause scaly patches and hair loss, which is more common in children and often needs a GP. Because other skin conditions can look similar, a pharmacist can usually help identify a typical rash, and a GP may occasionally take a skin sample if the diagnosis is unclear.

Fungal nail infections

When the fungus gets into a nail, usually a toenail, it causes a fungal nail infection. The nail may become thickened, brittle or crumbly, and change colour to white, yellow, green or brown; it can lift from the nail bed, become distorted in shape, and occasionally feel sore. Fungal nail infections often start after long-standing athlete's foot spreads to the nail. They are not dangerous for most people but can be unsightly and are notoriously slow to clear, because the nail grows slowly and treatment must last until healthy nail has fully grown out. This can take many months, especially for toenails. Anyone with diabetes, poor circulation or a weakened immune system should seek advice rather than self-treating, as foot infections can be more serious for them.

Treatment and self-care

Most skin fungal infections can be treated with over-the-counter antifungal creams, sprays or powders from a pharmacy, used exactly as directed and usually continued for a period after the rash clears to prevent it returning. A pharmacist can recommend a suitable product and check whether you need to see a GP. Fungal nail infections often need longer treatment, sometimes with a specially formulated nail preparation, and a GP may consider a course of antifungal tablets for stubborn cases after confirming the diagnosis. Alongside treatment, self-care limits spread and reinfection: keep skin and feet clean and dry, especially between the toes; do not share towels, socks or shoes; wear breathable footwear; and treat athlete's foot promptly to protect the nails.

When to see a GP

Many cases are handled well by a pharmacist, but some warrant a GP. See your GP if a skin infection does not improve after treatment from the pharmacy, keeps coming back, is widespread or severe, or affects the scalp, as scalp ringworm usually needs prescription treatment. Book an appointment for a fungal nail infection that is bothering you, spreading, or painful, since treatment choices differ and the diagnosis may need confirming. People with diabetes, poor circulation, or a weakened immune system should seek advice early for any foot or skin infection rather than waiting, because complications are more likely. If the skin around an infection becomes hot, swollen, increasingly red or painful, or you feel unwell, seek prompt medical advice, as this can suggest a bacterial infection.