Hyperpigmentation: Sun Spots vs Acne Marks vs Melasma

A dark mark on your face can come from three very different places: years of sun, a pimple that has long gone, or hormones and light working together. They look similar, but they behave differently, and the right approach is not the same for each.

Sun Spots (Solar Lentigines)

These flat, brown spots appear on skin that has seen years of sun: the cheeks, forehead, backs of the hands. Skin that is exposed to sunlight over many years tends to develop irregular pigmentation, and actinic (solar) lentigo is among the most common pigmented spots on sun-exposed skin^[1]. They are a record of cumulative UV exposure, which is why they tend to show up with age and why daily sun protection is the foundation for preventing new ones.

Acne Marks (Post-Inflammatory Hyperpigmentation)

After a pimple, bite, or irritation heals, skin can leave behind a flat dark mark. That is post-inflammatory hyperpigmentation, or PIH: inflammation switches on the pigment-making cells, which produce extra melanin in the affected spot. It is not a scar in the textured sense, and it is especially common in deeper skin tones. An expert panel of Indian dermatologists identified PIH as one of four priority pigmentation conditions in India and stressed prevention in skin types III to VI^[2]. The best way to prevent a mark is to avoid picking and to calm inflammation early.

Melasma

Melasma appears as larger, symmetrical, patchy brown areas, often on the cheeks, forehead, and upper lip. It is more complex than a sun spot: hormones, genetics, and light all play a part, and it tends to relapse. The same Indian expert consensus calls for combination approaches that address pigment production, inflammation, and sun protection together, and describes pigmentation disorders in skin of color as chronic and relapsing^[2]. Because it can be confused with other conditions, melasma is the one of the three where seeing a dermatologist for diagnosis is genuinely worth it.

Why Sunscreen Matters for All Three, and Why Visible Light Is the New Detail

Sun exposure is one of the most important factors in skin pigmentation, which is why sun protection is central to preventing pigmentation disorders^[3]. A newer finding is that ordinary UV protection may not be enough on its own: research increasingly implicates visible light, particularly blue-violet light, in melasma and PIH, especially in darker skin tones^[4]. In one analysis, melasma patients using an iron-oxide sunscreen, which blocks visible light, achieved better improvement than those using a UV-only sunscreen^[4]. Adherence matters too: fewer than two-thirds of people with hyperpigmentation use sunscreen, and fewer than 10% reapply appropriately^[4].

Which One Do You Have?

• Flat brown spots on sun-exposed areas, growing with age: most likely sun spots. Prevention is daily sunscreen.
• Dark marks exactly where pimples or irritation used to be: most likely PIH. Do not pick, calm inflammation early, and protect the area from the sun.
• Larger symmetrical patches on cheeks, forehead, or upper lip: possibly melasma. Get it assessed by a dermatologist.
• Mixed patterns are common, and all three darken with unprotected sun exposure.