Circular Dark Spots on Skin: Possible Causes

A flat brown mark may be post-inflammatory hyperpigmentation after a rash, bite, pimple, or injury. Sun spots tend to occur on repeatedly exposed areas, while melasma often affects broader, fairly symmetrical areas of the face. Tinea versicolor can produce lighter or darker patches with fine scale, commonly on the trunk. Shape alone is not diagnostic: note whether a spot is flat, scaly, itchy, raised, tender, or changing.

A clinician may use a close visual examination and, when needed, a simple surface test to separate pigment left behind from an active infection or inflammation. New or changing lesions should not be treated solely for colour before they are assessed.

Use broad-spectrum sun protection on exposed skin, wear protective clothing, and avoid picking or rubbing the spots. Keep a record of when each mark appeared and whether it followed irritation, medication, sun exposure, or a new skin product. Do not use unlabelled lightening products, strong peels, or home acids on an undiagnosed lesion. Once the cause is known, a clinician may discuss prescription care or options such as a chemical peel, skin brightening treatment, or picosecond laser treatment, with suitability based on skin type and the diagnosis.

Arrange a skin review for a spot that grows, changes colour or outline, bleeds, crusts, becomes painful, or differs clearly from nearby marks. Seek prompt care for rapid change, an open sore that does not heal, or multiple new lesions with illness. Also seek advice if dark patches appear after a new medicine or alongside widespread scaling, because the cause may need treatment rather than cosmetic care.

Does this look like pigment after inflammation, sun-related change, melasma, or an infection? Does the surface need testing? Which sunscreen and products suit my skin? Should I delay a peel or laser until the diagnosis is confirmed?