Can fungus cause black spots on the skin?

Fungal rashes more often have a pattern such as scale, an advancing edge, itch, altered hair or nails, or multiple patches. Pigment can also remain after the active rash has cleared.

Ringworm can present with an enlarging scaly border and relative clearing toward the centre, although the ring may be subtle. Tinea versicolor presents with finely scaling patches that are lighter, darker, or pink compared with nearby skin, commonly on the upper trunk, shoulders, or neck.

Scalp fungus may cause scale and broken hairs or patches of hair loss. Nail fungus can thicken and discolour a nail. A smooth solitary black lesion without scale may instead be pigment, a mole, dried blood, a foreign body, or another condition.

Keep the area clean and dry, change sweaty clothing, and avoid sharing towels, combs, hats, or razors while infection is possible. Photograph the border and surface so progression can be compared.

Avoid steroid cream on an undiagnosed rash because it can alter the appearance and allow some fungal infections to spread. A pharmacist or clinician can guide an appropriate antifungal for a typical limited rash; scalp, nail, widespread, or uncertain disease often needs medical assessment.

Arrange an appointment if the patch is spreading, recurring, affecting scalp or nails, or not improving with correctly used treatment. A skin scraping or other sample can sometimes separate fungus from eczema, pigment change, or a bacterial problem.

Prompt care is warranted for fever, pus, marked pain, rapid swelling, spreading warmth or redness, blisters, or involvement near an eye. An evolving dark lesion that bleeds, ulcerates, or differs from your other marks also needs direct examination rather than antifungal treatment.

Ask which visual features favour fungus, whether testing is needed, and how long the recommended medicine should be used. Mention contact sports, pets, shared grooming tools, recent travel, immune-suppressing medicines, diabetes, and any steroid or antifungal already applied.