Why does sun-damaged skin cause uneven skin tone?

Ultraviolet light stimulates pigment-producing cells as part of the skin’s protective response. With repeated exposure, some areas may make or retain more melanin than nearby areas. Existing pigment can also remain visible for longer as skin renews itself, producing freckles, sun spots or broader areas of uneven colour.

Tone changes may be more noticeable after inflammation from acne, eczema, a burn or an irritating product. Hormonal changes and some medicines can also alter pigmentation. A clinician can distinguish common sun-related changes from other causes by examining their pattern and history.

Apply broad-spectrum sunscreen to exposed skin every day and reapply as directed when outdoors. Hats, tightly woven clothing and shade reduce direct exposure. Avoid picking spots and stop products that sting or burn; irritation can leave darker marks after the skin heals.

For persistent patches, a dermatologist may consider prescription creams, chemical peels, laser or light-based procedures. Treatment choice depends on the pigment pattern, skin tone, trigger and risk of post-inflammatory darkening. Do not use unlabelled lightening products.

Seek a skin assessment for a new or rapidly changing dark spot, an irregular border, several colours in one lesion, bleeding, crusting or a sore that does not heal. These features need examination even when you also spend time in the sun.

Does the pattern fit sun-related pigmentation or another cause? Which sunscreen and treatment suit my skin tone? How can I reduce irritation, and what change should prompt a prompt review?