. Decoding Hyperpigmentation: Post-Inflammatory Marks, Melasma, Sun Spots, and How to Treat Each

"Hyperpigmentation" gets used as a catch-all term, but it actually covers several distinct conditions with different causes — and, critically, different treatment approaches. Using the wrong protocol on the wrong type of pigmentation is one of the most common reasons people feel like "nothing is working."

Post-inflammatory hyperpigmentation (PIH)

This is the dark mark left behind after a pimple, cut, insect bite, or any skin injury heals. It happens when inflammation triggers excess melanin production in the healing skin. PIH is more common and more pronounced in medium-to-deep skin tones, where melanocytes are more reactive to inflammatory triggers.

Treatment approach: Niacinamide, azelaic acid, vitamin C, and gentle exfoliation (retinoids or low-strength AHAs) all help fade PIH over time. The single most important factor, though, is sun protection — UV exposure darkens these marks further and significantly slows fading. PIH often resolves on its own over months, but consistent SPF use dramatically speeds that timeline.

Melasma

Melasma appears as larger, symmetrical patches, typically on the cheeks, forehead, upper lip, and jawline. It's driven by a combination of UV exposure and hormonal activity (estrogen and progesterone), which is why it's common during pregnancy or with hormonal birth control, and why it tends to flare with sun exposure and heat.

Treatment approach: Melasma is notoriously stubborn and can worsen with aggressive treatment. It responds best to a careful, gradual approach — azelaic acid, tranexamic acid, niacinamide, and strict, year-round SPF (including protection from visible light, not just UV, since visible light can also trigger melasma flares). Harsh exfoliation or high-strength actives can actually inflame melasma and make it worse, so this is a condition where "less but consistent" beats "aggressive."

Solar lentigines (sun spots / age spots)

These are flat, well-defined brown spots that develop from cumulative UV exposure over years, typically appearing on the face, hands, and chest. Unlike PIH, they aren't triggered by inflammation — they're a direct result of sun damage to melanocytes.

Treatment approach: Vitamin C, retinoids, and consistent SPF can lighten these gradually, but well-established solar lentigines often respond best to in-office treatments like chemical peels, laser therapy, or IPL, since topical treatment alone tends to produce slower, more modest results.

Post-inflammatory erythema (PIE) — the imposter

Often confused with hyperpigmentation, PIE is actually residual *redness*, not pigment, caused by damaged blood vessels after inflammation (common after acne). It looks pink or purple rather than brown and doesn't respond to pigment-targeting ingredients the way true hyperpigmentation does. Niacinamide and gentle barrier support help, but stubborn PIE sometimes needs vascular-targeted in-office treatment.

The one thing every type has in common

Regardless of the type of pigmentation, daily broad-spectrum SPF is non-negotiable. Without it, any topical treatment is working against a constant source of new pigment stimulation — which is why so many people feel like their brightening serum "isn't working" when the real gap is inconsistent sun