What should you know about black ringworm?

Ringworm can present with an enlarging circular or oval rash, often with a scaly, more active edge. On deeper skin tones, inflammation may look brown, grey, purple, or darker than the surrounding skin rather than bright red.

A dark centre or border can be pigment left after inflammation. A very dark, rough surface may instead be dried blood or crust from scratching. Ringworm is caused by a fungus, but other rashes can also form rings, so colour and shape are not enough to identify it.

Features worth noting include itch, scale at the border, gradual outward spread, hair loss within the patch, recent contact with an affected person or animal, and whether similar areas have appeared elsewhere.

Keep the area clean and dry, avoid scratching, and do not share towels, clothing, combs, or sports equipment. Wash hands after touching the patch. Take a clear photo in consistent lighting and note whether its border expands over several days.

Avoid steroid cream unless a clinician has advised it for this specific rash, because steroids can alter a fungal rash and make it harder to recognise. A pharmacist or clinician can help choose an antifungal when ringworm is suspected; scalp, nail, widespread, or persistent infection may require prescription assessment.

Arrange a clinical review if the diagnosis is uncertain, the patch is spreading, treatment has not helped, or the area involves the scalp, beard, nails, face, or groin. Seek prompt care for increasing pain, warmth, swelling, pus, fever, rapidly darkening tissue, blistering, or an open sore.

Earlier assessment is sensible for a baby, during pregnancy, or when diabetes, poor circulation, or a weakened immune system may affect healing or treatment choice.

Ask whether the border and scale fit a fungal infection, whether a skin scraping would clarify the diagnosis, and whether treatment should be topical or oral. Mention recent creams, affected household members or pets, and any change in hair or nails.