Sun Damage, Age Spots & Sun Spots: What to Watch For

Solar lentigines are flat, well-defined brown patches caused by localized overproduction of melanin in response to cumulative UV exposure. They appear most often after age 40 on areas that have received the most sun: face, backs of hands, forearms, chest, and shoulders.

They are completely benign and do not become skin cancer. They are a visible marker of sun exposure — essentially a cosmetic concern, not a medical one.

Sun spots (solar lentigines): flat, uniform color (light to medium brown), well-defined borders, round or oval, stable over time, not raised.

Melanoma: may be flat or raised, multiple colors (brown, black, red, white, blue), irregular borders, asymmetric, changing in size or appearance.

The critical question: is the spot stable, or is it changing? A sun spot that has looked the same for years is almost certainly benign. Any pigmented spot that is new, changing, or looks different from everything around it deserves a dermatologist's evaluation.

Seborrheic keratoses (SKs) are another very common benign growth that appears after 30-40. They look like waxy, stuck-on brown bumps — sometimes mistaken for melanoma because they can be dark and irregular-looking.

Key difference: SKs have a pasted-on appearance, as if you could peel them off. They often have a rough, warty surface. They are harmless but can be removed for cosmetic reasons.

Actinic keratoses (AKs) are rough, sandpapery patches on sun-exposed skin — often easier to feel than see. They are precancerous: about 5-10% progress to squamous cell carcinoma if untreated. If you run your hand over your forearm, face, or scalp and feel rough patches that do not go away with moisturizer, see a dermatologist.

Lentigo maligna is a type of melanoma in situ that occurs on severely sun-damaged skin, typically on the face of older adults. It looks like an irregular, expanding brown patch — unlike the flat, stable appearance of a typical sun spot.

Sun spots are permanent markers of past UV exposure. You cannot undo them, but you can prevent new ones. SPF 30+ daily on face and hands year-round. Wide-brim hat outdoors. UV-protective sunglasses.

For cosmetic improvement: topical retinoids, vitamin C serums, and professional treatments (chemical peels, laser, IPL) can lighten existing sun spots. But these are cosmetic — the medical priority is preventing new UV damage and monitoring existing spots for changes.