What should you know about what causes ringworm in humans?

Despite its name, ringworm is not a worm. Dermatophytes use keratin, a protein in the outer skin, hair, and nails, as a place to grow. Transmission can occur through direct skin contact or through shared towels, clothing, footwear, grooming tools, floors, or bedding. Warm, damp areas and small breaks in the skin can make fungal growth easier.

The condition may appear as an expanding scaly rash, itch, cracking between toes, scalp scale with broken hairs, or thickened discoloured nails. Other rashes can look similar, so a clinician may examine the area or take a sample when the diagnosis is uncertain.

Keep the affected skin clean and dry, wash hands after applying medicine, and avoid sharing personal items. Launder towels, clothes, and bedding regularly; clean footwear and grooming tools that contact the area. A clinician or pharmacist can guide topical antifungal treatment for some skin infections, while scalp or nail involvement may need oral medicine.

Use the treatment for the advised duration even if the surface looks better sooner. Steroid cream used alone can hide fungal changes and allow them to spread, so seek advice before applying it to an unexplained rash. Consider whether a household member or pet has symptoms that need assessment.

Arrange medical review when the rash involves the scalp, beard, nails, face, or a large area, or when it keeps spreading despite appropriate treatment. Seek prompt help for severe pain, pus, marked swelling, fever, or a painful scalp swelling. People with diabetes, reduced immunity, or recurrent infection should ask for individual treatment guidance.

Ask which body site is affected, whether testing is needed, whether topical or oral antifungal treatment is appropriate, how to clean shared items, and whether close contacts or pets should be checked.