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Hyperpigmentation

Also known as: hyperpigmentation, pigmentation, uneven pigmentation, dark patches

Hyperpigmentation describes skin that appears darker than its surrounding baseline. It is a sign, not one diagnosis: melasma, post-inflammatory hyperpigmentation and solar lentigines have different patterns and causes, while a suspicious or uncertain focal pigmented lesion needs medical assessment first.

Evidence status

Moderate

Common clinical patterns and NICE referral features are well described, but visual overlap is substantial and no cosmetic device or colour-based rule can establish every diagnosis or pigment depth. NICE guidance applies in England; devolved and local pathways may differ.

Definition#

“Hyperpigmentation” tells you what the eye can see: an area is darker than the skin around it. It does not tell you why.[1, 2]

That missing why is the whole of this entry. It is the difference between a treatment that works, a treatment that makes things worse, and a treatment that delays a diagnosis someone needed.

This page does not repeat the melasma or PIH entries. It exists to help you decide which one you are looking at — or whether you should be treating at all.

Before anything else: is it safe to treat?#

This question comes first, before pattern, before depth, before product. Not because it is common, but because it is the only one with an irreversible wrong answer.

A suspicious or diagnostically uncertain focal pigmented lesion should not be treated cosmetically. It should be directed for medical assessment.[7, 8, 9]i

In England, NICE uses a weighted seven-point checklist — major features scoring 2, minor features scoring 1 — alongside a separate criterion for nodular melanoma. Local and devolved pathways may differ, so know the one that applies where you practise.

The reason this threshold sits so low is the overlap. Early lentigo malignacan resemble a solar lentigo both clinically and on dermoscopy — the two are genuinely difficult to separate, and that difficulty exists for dermatologists with a dermatoscope, not just for practitioners without one.[6, 7]

Two things the checklist will not do for you. It has no site criterion— so it will not prompt you to look at palms, soles or nail units. As an MSTA precaution, treat a new or changing lesion at any of those sites as needing medical assessment whatever the score, and do the same for any unexplained, changing, asymmetric or diagnostically uncertain lesion.[8]i

And if you are treating a single pigmented lesion rather than a pattern, ask why. Cosmetic laser is not a diagnostic or definitive treatment pathway for a suspected lentigo maligna: it can alter the visible lesion, delay diagnosis and complicate later assessment.[7]i This page used to say that lasering a lentigo maligna “removes the visible evidence of it”. The conclusion was right and the mechanism was overstated — no source here shows that every laser erases every trace. The reason not to do it is that you would be interfering with a diagnosis.

And no, the imaging system does not settle it. We looked for validation evidence that any consumer or salon imaging system can substitute for medical examination of an uncertain lesion, and found none.[no source found]

Working the differential#

Once lesion safety is settled, the useful questions are about pattern and history rather than colour alone.

AskPoints towardsBecause
Is it one lesion or a pattern?One lesion → assess before treatingFocal lesions carry the referral question
Was there inflammation or injury here first?PIHPIH follows a specific event in the same distribution
Are the patches patterned across the face?MelasmaA characteristic distribution rather than a random one
Is it on chronically sun-exposed skin, and persistent?Solar lentigoWell-demarcated, does not fade seasonally
Is the mark pink or red rather than brown?Possibly vascular, not melaninPost-inflammatory erythema is a different target
Any systemic symptoms alongside it?Medical assessmentPigment can be a sign of systemic disease

This is a reasoning aid, not a diagnostic algorithm. Conditions coexist — a client can have melasma and PIH and a lentigo, and the melasma can have PIH on top of it from the last treatment.

Melasma#

Flat brown or grey-brown facial patches in a characteristic distribution suggest melasma. Pattern recognition is a starting point, not a diagnosis.[1]i

One note on precision. Melasma commonly presents as bilateral or symmetrical facial macules or patches, and this page previously under-stated that — on the basis that the particular patient leaflet we had selected did not use the word. A gap in our source set is not a gap in the evidence base, and we should not have written it as one. Symmetry is a clue, not a stand-alone diagnosis: asymmetry should prompt closer assessment rather than automatic exclusion.

The condition itself — its course, its triggers, and why aggressive treatment backfires — is covered in the melasma entry, linked under Related entries below.

PIH — and PIE#

Pigment appearing in the same distribution as preceding inflammation or injury is characteristic of post-inflammatory hyperpigmentation. The history does most of the diagnostic work.[1, 4]

Persistent pink-to-red marks after acne may be something else entirely: post-inflammatory erythema, a vascular change rather than a melanin one.[12]i

Be careful how much weight you put on that distinction. It is clinically useful and widely taught, but it was proposed in a two-case commentary— not established by a large series. Two cases cannot tell you how common it is, or define every colour presentation. Use it as a prompt to look at whether a mark blanches, not as a settled taxonomy.

Full detail in the PIH entry, linked under Related entries below.

Solar lentigines#

A solar lentigo is typically a persistent, well-demarcated flat or slightly raised pigmented lesion on chronically sun-exposed skin. Unlike a freckle it does not fade appreciably between summers.[1, 6]

These are the lesions most often treated casually with IPL or laser, and they are also the ones that overlap with early lentigo maligna. The clinical rule that follows is simple: a lentigo you are confident about on a body site that makes sense is one thing; an atypical, changing or solitary facial lesion in an older client is a referral, not a treatment.

When pigment is a systemic sign#

Pigmentation is occasionally the visible edge of something systemic. NICE advises considering adrenal insufficiency in people with unexplained hyperpigmentation, orwith the associated systemic features — the two do not both have to be present, and the pigmentation does not have to be widespread.[11]

NICE also notes the limits of visual recognition in black or brown skin, which is exactly the population in whom pigment change is most likely to be attributed to something cosmetic.

This is squarely outside aesthetic scope. The action is a referral and a clear note, not a lightening protocol.

Assessing depth#

Epidermal pigment behaves differently from dermal pigment, so estimating depth is genuinely useful. The tools are weaker than their reputation.

In a 50-patient comparison, Wood’s lamp and dermoscopy agreed only moderatelyon melasma depth category (Cohen’s kappa 0.534). A Wood’s lamp finding is information, not a classification.[10]i

Where depth genuinely changes the plan, that is an argument for medical assessment rather than for buying a better lamp.

In professional practice#

The sequence that keeps practitioners out of trouble:

  1. Lesion safety first. One focal lesion? Assess and refer before anything cosmetic.
  2. Then diagnosis. Melasma, PIH, lentigo or something else — they are not interchangeable.
  3. Then the trigger. Active inflammation, friction, hormonal context, light exposure.
  4. Then, and only then, the plan.Matched to the diagnosis, not to the word “pigmentation”.

Treating in the wrong order is how a peel gets used on melasma and leaves it worse, and how an energy-based device gets pointed at something that needed a biopsy. In one systematic review, PIH worsened in 2.6% of patients treated with laser and energy-based devices.[1, 2, 4, 5, 7, 8, 9]i

For a worked example on a specific body site — where hair shadow, friction, ingrown hairs and dermatitis all masquerade as pigmentation — see the underarm hyperpigmentation guide.

What remains uncertain#

  • How reliably any non-invasive tool classifies pigment depth in an individual.
  • How common post-inflammatory erythema actually is — the distinguishing work is a two-case commentary.
  • How often cosmetic treatment of pigmented lesions delays a malignant diagnosis. No dataset quantifies this.
  • Whether any imaging system marketed to salons has diagnostic value for lesion assessment.

Common misconceptions#

“Hyperpigmentation is a condition.”

It is a sign with several possible causes and no single treatment pathway.[1, 2]

“If it’s brown, it’s pigment — treat it.”

A single focal lesion carries a referral question that a pattern does not. Early lentigo maligna can look like a solar lentigo.[6, 7]

“A Wood’s lamp tells you the depth.”

It agreed with dermoscopy only moderately in the study that compared them.[10]i

“My skin scanner can screen it.”

No validation evidence was located for any salon imaging system as a substitute for medical examination.[no source found]

“Melasma is always symmetrical.”

Melasma commonly presents bilaterally or symmetrically, and that is a real and useful clue. What it is not is a stand-alone diagnosis: asymmetry should make you look harder rather than rule melasma out.[1]i

“It's just a dark patch — the medicines history can wait.”

Ask four things before you treat: did the change begin after starting a medicine; is it slate-grey or blue-grey rather than brown; does it follow a photodistribution; and does it involve mucosae, nails or the sclerae? Any of those should route the person to their prescriber or an appropriate medical clinician rather than into cosmetic brightening. We register no source for a drug-pigmentation differential here — this is a history prompt, and the reason to take it is that a medicine-related change treated cosmetically is a change nobody investigates.

Frequently asked questions#

A client has one dark spot they want removed. What do I do?

Establish whether it is safe to treat before deciding how to treat it. A solitary focal pigmented lesion — especially if it is new, changing, atypical or on the face of an older client — goes for medical assessment first.[7, 8, 9]i

How do I tell melasma from PIH?

Mostly by history. PIH follows a specific inflammatory or injury event in the same distribution; melasma appears in a characteristic facial pattern without one.[1, 4]

Why do some post-acne marks not respond to pigment treatment?

Because they may not be pigment. Pink-to-red marks may be vascular post-inflammatory erythema, which is a different target.[12]i

When is pigmentation a medical issue rather than a cosmetic one?

When the lesion is uncertain or suspicious, when there is unexplained pigmentation, or when systemic features are present. NICE treats unexplained hyperpigmentation as sufficient on its own to consider adrenal insufficiency.[11]

Can I just treat it and see?

No. Treatment can worsen the thing you are treating — PIH worsened in 2.6% of patients on energy-based devices in one review — and on a focal lesion it removes visible evidence without removing the problem.[1, 2, 4, 5, 7, 8, 9]i

References#

Each source is graded by evidence tier. Tier 4 material (manufacturer documents, expert consensus, practitioner experience) is useful for protocol and context, and is never presented as equivalent to independent clinical evidence.

  1. Wang RF, Ko D, Friedman BJ, Lim HW, Mohammad TF. Disorders of hyperpigmentation. Part I. Pathogenesis and clinical features of common pigmentary disorders. Journal of the American Academy of Dermatology. 2023;88(2):271–288.Tier 4Supports: Narrative clinical differential across epidermal, dermal and mixed hyperpigmentation disorders. NOTE: this paper states that systemic causes 'were largely excluded and considered to be outside the scope of this review', so it does NOT support any systemic-pigmentation claim.Funding / interest: Read from the PubMed record: Dr Lim holds investigator roles with multiple pharmaceutical companies and consults for several skincare firms; Dr Mohammad holds investigator positions with various organisations; Drs Wang, Ko and Friedman declare none. DOI 10.1016/j.jaad.2022.01.051.
  2. Passeron T, Desai SR, Abdallah M, et al. Global consensus on the management of melanin hyperpigmentation disorders. Journal of the European Academy of Dermatology and Venereology. 2026;40(5):760–772.Tier 4Supports: Diagnosis-specific assessment across common pigment disorders.Funding / interest: CORRECTED 2 Aug 2026 — this entry previously recorded 'Beiersdorf grant 001/2025', which the paper does not report. Its actual statement, verbatim: 'Editorial assistance was provided by Beiersdorf. The sponsor had no role in the study design, data collection, analysis, interpretation or decision to submit the manuscript.' Nine of the ten authors report conflicts of interest — consulting honoraria, lecture payments, meeting support and investigator roles across Beiersdorf, Pfizer, Incyte, AbbVie, Janssen, L'Oréal, Pierre Fabre, Novartis and others; one author declares none.
  3. British Association of Dermatologists. Melasma: Patient Information Leaflet. Updated June 2024; next review June 2027.Tier 4Supports: UK professional consensus on typical melasma presentation and when medical diagnosis is needed to exclude another condition. NOTE: this leaflet does not describe melasma as symmetrical, so it cannot carry a symmetry claim.
  4. Davis EC, Callender VD. Postinflammatory Hyperpigmentation: A Review of the Epidemiology, Clinical Features, and Treatment Options in Skin of Color. Journal of Clinical and Aesthetic Dermatology. 2010;3(7):20–31.Tier 4Supports: The inflammation-or-injury history of PIH, epidermal and dermal colour patterns, and cause-first management. NOTE: this paper does not mention erythema anywhere, so it cannot support the vascular half of the PIH-versus-PIE contrast.
  5. Kashetsky N, Feschuk A, Pratt ME. Post-inflammatory hyperpigmentation: A systematic review of treatment outcomes. Journal of the European Academy of Dermatology and Venereology. 2024;38(3):470–479.Tier 1Supports: 41 studies, 877 patients. Evidence is acne-heavy, complete clearance uncommon, and PIH worsened in 2.6% (8/309) of those treated with laser and energy-based devices.
  6. Fitzpatrick A, Chan J. Solar lentigo. DermNet. Peer reviewed by Ngo B; reviewed November 2025.Tier 4Supports: Clinician-reviewed solar-lentigo pattern, persistence, sun-exposed distribution, and the differential from melanoma in situ and keratinocytic lesions.
  7. Tanaka M, Sawada M, Kobayashi K. Key points in dermoscopic differentiation between lentigo maligna and solar lentigo. Journal of Dermatology. 2011;38(1):53–58.Tier 4Supports: Diagnostic overlap between early lentigo maligna, solar lentigo and other flat pigmented facial lesions, including overlap in dermoscopic features.
  8. National Institute for Health and Care Excellence. Suspected cancer: recognition and referral. NICE guideline NG12.Tier 1Supports: Suspected-melanoma referral criteria FOR ENGLAND. 1.7.1: refer using a suspected cancer pathway referral for melanoma if there is a suspicious pigmented skin lesion with a weighted seven-point checklist score of 3 or more. MAJOR features, 2 points each: change in size; irregular shape; irregular colour. MINOR features, 1 point each: largest diameter 7 mm or more; inflammation; oozing; change in sensation. 1.7.2: refer if dermoscopy suggests melanoma. 1.7.3: consider referral for a pigmented or non-pigmented lesion that suggests nodular melanoma. NOTE WHAT IT DOES NOT DO: the checklist contains no site criterion, so it does not by itself prompt scrutiny of palms, soles or nail units. Local and devolved pathways may differ.
  9. National Institute for Health and Care Excellence. Melanoma: assessment and management. NICE guideline NG14.Tier 1Supports: Dermoscopy of referred pigmented lesions by trained healthcare professionals, and specialist monitoring of selected atypical lesions.
  10. Navya A, Pai V. Comparison of dermoscope and Wood's lamp as a tool to study melanin depth in melasma. Indian Dermatology Online Journal. 2022;13(3):366–369. doi:10.4103/idoj.idoj_245_21.Tier 3Supports: Only moderate agreement (Cohen's kappa 0.534) between Wood's lamp and dermoscopic depth categories in 50 patients.
  11. National Institute for Health and Care Excellence. Adrenal insufficiency: identification and management. NICE guideline NG243.Tier 1Supports: NICE advises considering adrenal insufficiency in people with unexplained hyperpigmentation OR with the listed systemic features — not only when both are present — and notes the limits of visual recognition in black or brown skin.
  12. Bae-Harboe YSC, Graber EM. Easy as PIE (Postinflammatory Erythema). Journal of Clinical and Aesthetic Dermatology. 2013;6(9):46–47.Tier 4Supports: A brief TWO-CASE commentary proposing post-inflammatory erythema terminology for persistent pink-to-red post-acne macules. It is a terminology paper, not an observational cohort and not a consensus statement: two cases cannot define frequency or every colour presentation. Typed narrative-review as the most conservative available fit, and described here so the type does not have to carry the caveat.

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Skinipedia is written by the educators at MSTA, the medic-led skincare training academy in Liverpool.