Post-inflammatory pigmentation develops after the skin has experienced inflammation or injury — including acne, eczema, psoriasis, cuts, burns, insect bites, or even some cosmetic procedures. As the skin heals, it can be left with a flat mark of discolouration in the area, which may be darker (post-inflammatory hyperpigmentation) or, less commonly, lighter (post-inflammatory hypopigmentation) than the surrounding skin.
This type of pigmentation is more common, and often more pronounced and slower to fade, in people with darker skin tones. It generally isn't permanent, but it can take many months, and sometimes over a year, to fade on its own, and ongoing sun exposure to the area can prolong it or make it darker in the meantime.
Treatment approach depends heavily on the underlying cause, but some principles apply across the board:
Because treatments that work well for one type of pigmentation can be ineffective — or even counterproductive — for another, getting the diagnosis right before starting treatment makes a real difference to your results.
Pigmentation occurs when melanin, the pigment that gives skin its colour, is produced in excess or unevenly distributed in an area of skin. Various triggers can switch on melanin-producing cells (melanocytes), including UV exposure, hormones, and inflammation — which is why sun damage, melasma, and post-inflammatory pigmentation, despite looking broadly similar, often need quite different treatment strategies.
Melasma causes symmetrical brown or grey-brown patches, most often on the cheeks, forehead, and upper lip, driven by a combination of hormonal factors (such as pregnancy or the contraceptive pill), UV and visible light exposure, and genetics. It behaves differently to sun damage pigmentation — it's more stubborn, can worsen with heat and light rather than just direct sun, and needs a more specific, carefully managed treatment approach. Melasma is common enough, and different enough in its causes and treatment, that we've covered it in more detail on its own page.
Sun damage pigmentation, also known as solar lentigines or sunspots, refers to flat, brown spots that develop from cumulative UV exposure over years. They typically appear on the areas that get the most sun over a lifetime — the face, hands, forearms, and chest — and become more common with age. Unlike a normal freckle, solar lentigines tend to persist year-round rather than fading in winter, and they can gradually increase in number and become more pronounced with ongoing sun exposure.
While solar lentigines are benign, any new or changing pigmented spot is worth having checked by a dermatologist, since some early skin cancers, including melanoma, can be mistaken for a sunspot in their early stages.