Hyperpigmentation: PIH, Melasma, and Sun Damage

Hyperpigmentation is a catch-all term for areas of skin that appear darker than the surrounding skin due to excess melanin. But the "why" behind each type is different — and so is what actually helps.

Post-inflammatory hyperpigmentation (PIH)

PIH is the dark mark left after a breakout, burn, or skin injury. It is not a scar — there is no textural change. It is melanin overproduction triggered by the inflammatory process. PIH is more pronounced in deeper skin tones, where melanocytes are more reactive.

• SPF daily — UV darkens PIH significantly and prolongs its duration.
• Niacinamide — interrupts melanin transfer to skin cells, fading marks over time.
• Vitamin C — inhibits tyrosinase, the melanin-production enzyme.
• Azelaic acid — anti-inflammatory and tyrosinase-inhibiting; particularly good for PIH in sensitive skin.
• Retinoids — accelerate cell turnover, bringing pigmented cells to the surface faster.
• Timeline — even with treatment, PIH typically takes 3–24 months to fully fade.

Melasma

Melasma is a symmetrical, patchy hyperpigmentation typically affecting the face (cheeks, forehead, upper lip). It is strongly associated with hormonal changes (pregnancy, contraceptives) and UV exposure. It is notoriously difficult to treat and prone to relapse.

• Hydroquinone — the most studied depigmenting agent; prescription-strength (4%) most effective. Not for continuous long-term use.
• Tranexamic acid — newer strong evidence, well-tolerated, and a first-line option.
• Triple combination cream (hydroquinone + tretinoin + steroid) — prescription; the most evidence-supported for melasma.
• Chemical peels and lasers — adjunct options but carry higher risk in darker skin tones.

Sun damage (solar lentigines)

Solar lentigines ("age spots", "liver spots") are flat, well-defined dark spots caused by cumulative UV exposure. They are distinct from melasma — no hormonal component — and respond reasonably well to topical brighteners and laser treatments.