Why does hyperpigmentation cause dark patches on skin?

Melanin is the pigment that gives skin its colour. When production increases, or pigment is transferred into nearby skin cells, an area can look brown, grey-brown, or darker than the surrounding skin. This change may follow inflammation from spots, eczema, irritation, an injury, or sun exposure. Hormonal changes and some medicines can also influence pigment activity. The shade and pattern depend on how deeply the pigment sits in the skin.

Dark patches can be flat and may have a clear or uneven edge. Their appearance alone cannot identify the cause, so a clinician may ask when they began, whether they change, and what products or medicines touch the area.

Use gentle, fragrance-free skincare and avoid picking, scrubbing, or repeatedly applying products that sting. Protect exposed skin from sunlight with shade, clothing, and broad-spectrum sunscreen, because ultraviolet light can deepen existing pigment. Treating an active rash or acne problem can help prevent new patches. A dermatologist can distinguish pigment changes from other marks and discuss options such as prescription creams, peels, or light-based treatment when appropriate.

Arrange a skin assessment if a patch is new and changing, has an irregular border, bleeds, crusts, feels persistently sore, or differs noticeably from your other marks. Seek advice sooner when pigmentation appears widely, follows a new medicine, or comes with a rash or other symptoms. Prompt review helps clarify whether the change is simple post-inflammatory pigment or needs a different evaluation.

Ask what pattern of hyperpigmentation fits your patches, whether an earlier rash or product may have triggered them, and how long improvement might take. You can also ask which sunscreen and active ingredients suit your skin, whether testing is needed, and how to reduce the chance of darker marks after irritation.