Post-Inflammatory Hyperpigmentation in Skin of Colour: Causes, Care and When to Get Help

Dark marks that linger long after a spot, a patch of eczema or a scrape has actually healed. Not a scar exactly, and not the original condition either — just a stubborn shadow of pigmentation that can take months to fade, and that sometimes bothers someone more than whatever caused it in the first place.

This article covers what post-inflammatory hyperpigmentation (PIH) is, why it shows up more often — and can last longer — in skin of colour specifically, what's known to help, and when it's worth seeing a dermatologist rather than waiting it out.

What is post-inflammatory hyperpigmentation?

Post-inflammatory hyperpigmentation is dark or discoloured patches of skin that appear after inflammation or injury has already healed — it's the aftermath, not the original problem. Acne, eczema, insect bites, cuts, burns, and even certain skincare or dermatology procedures can all trigger it. The mechanism: inflammation stimulates melanocytes, the skin's pigment-producing cells, into making more melanin than usual, and that extra pigment can sit in the skin for weeks, months, or occasionally longer, after whatever caused it is gone.

It isn't the same as a scar. A scar involves a change in the skin's texture; PIH is purely a change in colour, on skin that has otherwise healed normally. The two can occur together, but they're different things and can need different approaches.

Why it shows up more — and can last longer — in skin of colour

PIH can affect anyone, but it's disproportionately common, and often more persistent, in skin of colour — a broad clinical term covering a wide range of deeper skin tones across many different ethnic backgrounds, not a single group. Part of the explanation is mechanical: in more deeply pigmented skin, more melanosomes — the structures that carry pigment inside skin cells — tend to be produced and transferred in response to the same degree of inflammation, leaving more visible pigment behind once the original inflammation has cleared. The scale of the difference has been studied directly in acne: in one widely cited study, 65.3% of African-American, 52.7% of Hispanic and 47.4% of Asian participants who had acne went on to develop some degree of post-inflammatory hyperpigmentation. Those figures come from a single study with relatively small patient groups, particularly for the Asian cohort, but they're consistent with the broader pattern in the literature that acne-related PIH is markedly more common in skin of colour than in lighter skin.

For many people in this group, the marks left behind by a breakout or flare can end up being a bigger long-term concern than the original spot or patch — dermatology literature increasingly treats PIH as a quality-of-life issue in its own right, not just a cosmetic afterthought.

What can trigger it

Almost anything that inflames or injures the skin can leave PIH behind. The most commonly reported triggers include acne — by far the most researched cause — eczema and other inflammatory skin conditions, cuts, burns, insect bites and friction, and cosmetic or dermatology procedures such as waxing, chemical peels or laser treatments, which can occasionally cause the exact problem they're meant to treat if the skin reacts to the procedure itself.

Because PIH follows on from inflammation of any kind, keeping the skin barrier in reasonable shape — covered in more depth in our guide on supporting a stressed barrier — is a sensible general habit for avoiding unnecessary irritation, though it isn't a proven way to prevent PIH specifically.

Epidermal vs dermal — why the timeline varies so much

Not all PIH behaves the same way, and the difference matters for what to expect. Epidermal PIH, where the extra pigment sits in the outer layer of skin, is generally tan to dark brown and can take up to 12 months to fade. Dermal PIH, where pigment has moved deeper into the skin, tends to look blue-grey and can persist for years.

Colour alone isn't a substitute for a professional diagnosis, particularly where the cause of the pigmentation itself is uncertain — this is one of the clearer cases where a dermatologist's assessment is genuinely useful rather than optional.

What dermatologists use to treat it

A range of treatments is used for PIH, but response varies from person to person, and the evidence is stronger for some approaches than others. A 2024 systematic review covering 46 studies and over 1,300 people with skin of colour found a lack of robust efficacy across treatment modalities overall — most approaches produced partial improvement for some people, but full resolution was uncommon and results varied considerably between studies. Topical retinoids and azelaic acid are commonly used first-line options. Hydroquinone is one of the most established treatments, but in the UK it's available only on prescription — it isn't permitted in over-the-counter cosmetics — so it needs a GP or dermatologist's involvement rather than a general skincare routine. Chemical peels and certain lasers can also help, though because they work by controlled injury to the skin, they carry a real risk of making pigmentation worse if used inappropriately.

If pigmentation is persistent, extensive or difficult to identify, professional advice can help distinguish PIH from other causes of pigmentation and work out whether a prescription or procedural treatment is likely to help — this isn't something Nurest, or any cosmetic skincare brand, is positioned to provide.

What can help on the cosmetic side while it settles

Alongside any dermatologist-directed treatment, a few everyday habits may help avoid making things worse while pigmentation is settling:

• Use broad-spectrum SPF 30+ daily — from day one, don't skip it. Sun exposure is one of the clearest, most consistently cited factors in making existing pigmentation darker and slower to fade, even after things have already improved.
• Avoid picking, scratching or over-treating the original spot or patch. Additional trauma to already-inflamed skin is a recognised way to add more pigmentation on top of what's already there.
• Keep the rest of the routine gentle while skin is settling. Over-cleansing, excessive exfoliation or products that cause ongoing irritation can add fresh irritation to skin that's already dealing with inflammation, which doesn't help. Our guide on cleansing without stripping the skin barrier covers this in more depth.
• Avoid introducing several new active ingredients at once. It's harder to tell what's helping, and easier to trigger fresh irritation — and therefore fresh pigmentation — if multiple products change together. Our guide on reading an ingredient list can help you introduce things one at a time.
• Expect this to take time. PIH can take months to fade, so repeatedly changing products in pursuit of a quick result may introduce additional irritation rather than speed anything up.

When to speak to a professional

It's worth seeing a GP or dermatologist if the discolouration is widespread, isn't improving after several months, is affecting your confidence, or if you're not sure whether you're dealing with PIH, melasma, or something else — these can look similar but often need different approaches. A dermatologist can also advise on prescription-strength options like hydroquinone, or in-clinic treatments, if marks aren't settling on their own. If you're already using a prescribed treatment for whatever caused the PIH in the first place — an eczema flare, for example — don't stop or change it without speaking to the prescriber first.

Common questions about post-inflammatory hyperpigmentation