What should you know about ring fungus on skin?

Ring fungus on skin is a contagious fungal infection that often causes an expanding, scaly ring-shaped rash with clearer skin toward the centre. It may itch, crack, or spread to nearby areas. The name refers to the shape of the rash, not to a worm under the skin.

Ring fungus is a surface infection caused by dermatophytes, fungi that live on skin, hair, and nails. The edge of a lesion may be more raised, red, or scaly than its centre. It can affect the body, groin, feet, scalp, or nails, and can pass through close skin contact or shared towels, clothing, sports equipment, and grooming items. A similar-looking rash can also come from contact dermatitis, psoriasis, or other causes, so appearance alone cannot confirm the diagnosis.

Scratching can move the fungus to another body site and may damage the skin. Pets can sometimes carry fungal infection without an obvious rash, so recurring household infections deserve discussion with a clinician and a veterinarian.

Keep the area clean and dry, wash your hands after touching it, and avoid sharing towels, clothes, hairbrushes, or razors. Wear loose, breathable clothing and change damp garments promptly. A pharmacist or clinician can recommend an antifungal cream, lotion, or powder suited to the affected site; use it for the full instructed course even if the rash improves early. Do not apply a steroid cream by itself to an undiagnosed ring-shaped rash, because it can mask or worsen a fungal infection. Scalp, nail, widespread, or recurrent infection may need prescription treatment and examination.

Arrange medical advice if the rash is on the scalp or nails, involves a child, keeps returning, or does not improve with appropriate pharmacy treatment. Seek prompt care if the area becomes increasingly painful, hot, swollen, rapidly spreading, or drains pus, or if you develop fever or feel unwell; these features can signal a bacterial complication such as cellulitis. People with diabetes, reduced immunity, or extensive skin disease should seek advice early.

Ask whether the rash needs a skin scraping or another test, which antifungal product and treatment length fit its location, and whether close contacts or household pets should be checked. Tell the clinician about steroid creams, medicines, skin conditions, and any earlier episodes.