When the spot clears, why does the mark remain? The answer lies in understanding what that mark actually is — because a pink or red patch and a brown or darkened one are not the same problem, and they will not respond to the same treatment.
In clinic, this is something I see regularly. A patient has managed their breakout well — perhaps even avoided picking — and yet weeks on, there is still a visible reminder of where that spot was. What most people don’t realise is that two entirely separate biological processes can leave a mark after acne, and confusing the two is the single most common reason treatments fail. The wrong product, however consistently used, simply will not work.
Patient with PIH
Two different problems, two different solutions
The two conditions look superficially similar — both are flat marks left after a spot — but they have completely different causes and respond to completely different treatments.
| PIE
Post-inflammatory erythema A vascular response. When a pimple damages the dermis, tiny blood vessels dilate and become leaky, leaving a flat pink, red, or purplish mark. This is not pigment — it is dilated capillaries showing through the skin. More visible in fair to medium skin tones, though it can occur in any skin type. |
PIH
Post-inflammatory hyperpigmentation A melanin response. Inflammation triggers melanocytes to overproduce melanin as a defence mechanism, leaving a tan, brown, or grey-black flat mark. More prevalent and more stubborn in medium to dark skin tones (Fitzpatrick III–VI). The deeper the inflammation, the deeper pigment can sit. |
The glass test: Press a clean glass firmly against the mark. If the redness blanches (disappears), you are looking at PIE — dilated vessels, not pigment. If the colour stays, it is PIH, or a mix of both. Simple, free, and genuinely useful before spending anything on treatment.
Treatments that actually work
This is where patients go wrong most often — spending months on vitamin C and niacinamide serums for what is actually PIE. Those are excellent PIH ingredients. For PIE, they do almost nothing. It is worth understanding the two categories separately, because the approaches are genuinely different.
Treating PIE — the redness and vascular marks
Vascular laser
The most effective intervention for PIE is a laser that targets oxyhaemoglobin in dilated vessels — collapsing them without affecting the surrounding skin. Results are typically visible within 1–3 sessions and are far faster than any topical route. This should be the first conversation for anyone with persistent PIE.
Retinoids
By accelerating cell turnover and supporting dermal remodelling, retinoids gradually reduce the appearance of PIE over time. Start low and go slow — irritation sets back progress.
Niacinamide and anti-inflammatory skincare
Niacinamide helps reduce redness and supports barrier repair. It is a useful supporting ingredient but should not be the centrepiece of a PIE treatment plan.
SPF 50+ daily
UV prolongs vascular inflammation and slows resolution. Daily sun protection is non-negotiable alongside any treatment for PIE.
Treating PIH — the brown and darkened marks
Tyrosinase inhibitors
Tranexamic acid, kojic acid, azelaic acid, and alpha-arbutin interrupt melanin synthesis. These require 8–12 weeks of consistent use. There are no shortcuts — but they genuinely work when used correctly alongside sun protection.
Chemical exfoliation — AHAs
Glycolic and lactic acids speed up surface cell shedding, helping shift epidermal PIH. Avoid if skin is compromised or actively inflamed — exfoliating broken skin can trigger further PIH, particularly in darker skin tones.
Retinoids
As with PIE, retinoids help shift superficial PIH through accelerated cell turnover. Particularly useful when combined with tyrosinase inhibitors.
SPF 50+ daily
UV darkens PIH significantly. No topical or laser treatment works effectively without rigorous daily sun protection. This is the step most patients are inconsistent about.
Treatments available at Health & Aesthetics
For patients where home skincare alone is insufficient, we offer a range of clinic-based treatments specifically selected for their effectiveness against PIE and PIH. All treatments begin with an in-depth consultation to ensure the right approach for your skin type, tone, and the depth of the marks.
For PIE — targeting redness and dilated vessels
Excel® V+ Rosacea Laser
Our FDA-approved Cutera Excel V+ uses a high-power green laser to target blood vessels with precision, collapsing dilated capillaries without damaging surrounding skin. This is the most effective in-clinic treatment for persistent PIE and post-acne redness, typically requiring 1–3 sessions. It is suitable for all skin types (Fitzpatrick I–VI) and requires no anaesthesia.
Laser Genesis
Laser Genesis gently heats the upper dermis to reduce redness, diffuse thread veins, and promote collagen remodelling. It is a comfortable, no-downtime treatment particularly well suited to patients with generalised post-acne redness or sensitive skin.
HydraFacial & HydraGenesis
Our bespoke medicated HydraFacials incorporate anti-inflammatory boosters and can be tailored specifically for post-acne redness. HydraGenesis combines HydraFacial with Laser Genesis and LED light therapy for a more comprehensive result in a single session.
For PIH — targeting pigmentation and brown marks
Cosmelan Depigmentation Programme
Cosmelan is one of the most powerful depigmentation treatments available, combining an in-clinic application with a structured home maintenance protocol. It is particularly effective for deeper or more widespread PIH and for patients whose pigmentation has not responded to standard topicals alone. It targets multiple stages of the melanin production pathway simultaneously.
Chemical Peels
Our medical-grade chemical peels use AHAs and other active ingredients to accelerate epidermal shedding and reduce superficial PIH. The depth and formulation are always selected according to skin type — this is not a one-size-fits-all treatment, and getting the selection right is critical, particularly in darker skin tones.
For PIE and PIH
ZO® Skin Health
We are a ZO Skin Health stockist and incorporate ZO products into tailored skincare plans for both PIE and PIH. For pigmentation, products such as the Retinol Skin Brighteners (available in 0.25%, 0.5%, and 1%) are particularly effective alongside our in-clinic treatments.
HydraFacial
The HydraFacial is one of the few treatments that works for both conditions. Anti-inflammatory boosters calm vascular reactivity and redness in PIE, while the exfoliation and brightening serums help shift surface pigmentation in PIH. At Health & Aesthetics our HydraFacials are bespoke and medicated, with actives chosen specifically for your skin concern. For patients dealing with both PIE and PIH simultaneously — which is not uncommon — a course of HydraFacials is often the most practical starting point before moving on to laser or chemical treatments.
Realistic timelines
Setting honest expectations is one of the most important things I do in consultation. Superficial PIH treated consistently will improve — but not in two weeks. PIE treated with the right laser can actually clear faster than PIH.
| Weeks 2–4 | PIE: first visible improvement following vascular laser. With topicals alone, minimal change at this stage. |
| Weeks 6–8 | PIE post-laser: often 50–70% improved. PIH: first meaningful response to tyrosinase inhibitors plus consistent SPF becoming visible. |
| Weeks 12–16 | Epidermal PIH: significant improvement with consistent topicals or peels. Dermal PIH may need laser or Cosmelan, and will take longer. |
| 6+ months | Deep dermal PIH, especially in darker skin tones: longer treatment course with professional oversight is essential to avoid rebound hyperpigmentation. |
Why PIH is so much harder in darker skin
Melanocytes in darker skin tones are more reactive — they produce more melanin in response to less provocation. This is protective against UV damage, but it means even minor inflammation can trigger significant pigmentation. The cruel irony is that some powerful treatments — high-strength hydroquinone, aggressive peels, poorly calibrated lasers — can themselves cause PIH if used without proper expertise.
My clinical view: if you have Fitzpatrick skin type III or above and PIH that has not responded to three months of consistent topicals, please seek assessment. At our clinic, we assess each patient individually and select devices and settings appropriate to skin tone — the risk of post-treatment hyperpigmentation from poorly matched treatment is real, and I see the consequences of it regularly.
The habit that undoes everything
Picking. Patients know this. They still do it. Mechanically rupturing an inflamed follicle drives debris deeper into the dermis, prolongs the inflammatory response, and can turn mild PIE into deep dermal PIH. If I could choose one single intervention that would improve outcomes more than any serum or device, it would be convincing people to stop picking. Unglamorous, but true.
A note on melasma
Brown marks on the face are not always PIH. Melasma — hormonally driven pigmentation — can look identical and is significantly harder to treat. If your pigmentation is symmetrical, covers larger areas, and worsens with sun and hormonal changes, get a proper diagnosis before starting any treatment. Treating melasma as PIH wastes time at best and aggravates it at worst.
