Skin & hair

Telling Melasma From Other Dark Spots

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Three different things can leave a dark mark on skin, and they're often lumped together under one word. Melasma follows a hormone- and light-driven pattern of its own; post-inflammatory hyperpigmentation follows the shape of whatever injured the skin; sunspots build up individually from years of sun. Telling them apart is the first step toward treating the right one.

Last updated: July 2026

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Hyperpigmentation Is the Category; Melasma Is One Cause Within It

"Hyperpigmentation" is a broad, descriptive term for any patch of skin that's darker than the skin around it — it describes an appearance, not a cause. Melasma is one specific condition that produces hyperpigmentation, distinguished by a particular pattern, a particular set of triggers — genetics, hormones, and UV and visible-light exposure — and a tendency to affect women and people with darker skin types more than others 1. Two other common causes, covered below, produce hyperpigmentation through entirely different mechanisms: post-inflammatory marks left behind by injury or inflammation, and sunspots built up from years of cumulative sun exposure. Hyperpigmentation also sits at one end of a spectrum — the opposite, patches of skin losing pigment entirely, is vitiligo, a distinct autoimmune condition in which the immune system destroys melanocytes, unrelated to any of the causes of dark spots covered here 2. Knowing which category actually applies changes what helps, since a treatment aimed at melasma can be the wrong move for a sunspot, and vice versa.

What Makes Melasma Specifically

Melasma follows a fairly recognizable pattern: symmetric, blotchy patches — most often on the cheeks, forehead, upper lip, or bridge of the nose — that develop from an interaction of genetic predisposition, sex hormones, and exposure to UV and visible light, and it disproportionately affects women and people with darker skin types 1. Melasma's three documented drivers are genetics, sex hormones, and UV/visible-light exposure — not sun exposure alone. Because hormones are part of the trigger, pregnancy melasma is one of the more recognizable patterns clinicians see, along with melasma linked to hormonal contraception. That hormonal and genetic component is also why melasma tends to be more persistent and more prone to recurrence than a mark caused by a single injury that heals and fades on its own.

Post-Inflammatory Hyperpigmentation: When Skin Darkens After Injury

Post-inflammatory hyperpigmentation, often shortened to PIH, is a flat, discolored mark left behind after skin has been inflamed or injured — a healed acne lesion, an eczema flare, a scrape, or a bug bite can all leave one. Post-inflammatory hyperpigmentation is a mark that forms after inflammation or injury disturbs pigment-producing cells in the skin, distinct from an active lesion or an ongoing rash. Unlike melasma, PIH follows the shape of whatever caused it rather than a symmetric facial pattern, and it isn't tied to hormones or a genetic predisposition the way melasma is. Post-inflammatory hyperpigmentation vs erythema is a related distinction worth knowing, since acne in particular can leave either a brown-toned mark or a red one depending on skin tone and how deep the inflammation went, and the two fade on different timelines.

Sunspots and Age Spots: A Different Pattern Again

Sunspots — also called solar lentigines or age spots — are small, discrete, flat brown marks that accumulate individually over years of cumulative sun exposure, typically on the hands, face, chest, and other areas that get regular sun. They tend to show up as scattered individual spots rather than the larger, blended, symmetric patches typical of melasma, and unlike PIH, they aren't tied to a specific injury or inflammatory event — they build up gradually from years of light exposure instead. Someone can have more than one of these three at once — sunspots and melasma both respond to some of the same core habit, consistent light protection, even though the underlying mechanisms and some of the deeper treatments differ.

Why the Distinction Matters for Treatment

Because these causes of dark patches respond differently, matching treatment to the actual cause matters more than reaching for a product because it worked for someone else's spot. Hydroquinone and light protection, the backbone of most melasma treatment plan approaches, work differently on melasma than on PIH or sunspots, and using them on the wrong target either underperforms or wastes time better spent elsewhere. Procedures are where the distinction matters most: how laser and melasma interact is a more delicate question than how laser interacts with a simple sunspot, and that nuance is worth understanding before booking a procedure aimed at one thing that might actually be another. Melasma that doesn't respond to a standard approach — sometimes called stubborn melasma — is also a different conversation from a sunspot or PIH mark that simply hasn't been treated yet.

When to See a Dermatologist Instead of Guessing

Self-diagnosing a dark patch from an online description is unreliable, especially because melasma, PIH, and sunspots can overlap in appearance, and because access to a dermatologist for an in-person read isn't distributed evenly — dermatologists are disproportionately concentrated in metropolitan areas, which can make an in-person exam harder to get for people in rural areas specifically 3. Melasma in particular is diagnosed more reliably on skin of color when a clinician who regularly treats a range of skin tones examines it, since its patterns and its close look-alikes can present differently across skin types 1. When a dark patch doesn't fit neatly into any of these three categories, or keeps changing rather than staying stable, that's a reason for an actual exam rather than continued comparison to photos online.

Common questions

Yes — melasma and PIH aren't mutually exclusive, and having one doesn't rule out the other showing up separately, especially since inflamed skin from acne or a reaction to a harsh product can trigger PIH on top of an existing melasma patch. Sorting out which is which usually comes down to shape, location, and history rather than appearance alone.

No — they're different processes. Sunspots form individually from cumulative sun exposure over years, while melasma develops from a combination of genetics, hormones, and light exposure and tends to appear as larger, more symmetric patches. Someone can develop both, but one doesn't become the other.

Melasma disproportionately affects women and people with darker skin types, a pattern that's been consistently documented, though the exact reasons are tied to the same mix of genetic and hormonal factors that drive the condition generally. It doesn't mean lighter skin tones are immune to it.

Most hyperpigmentation — melasma, PIH, sunspots — is benign and cosmetic rather than dangerous. A patch that's changing shape, has irregular borders or multiple colors, or is growing rather than staying flat and stable is different from ordinary hyperpigmentation and is worth having examined rather than assumed benign.

Not reliably. Light protection helps across all three, but the active treatments differ enough — melasma often needs hormonally-aware, light-protection-first management, while PIH frequently fades with time and sunspots respond to different procedures — that a single product marketed as a universal dark-spot corrector is unlikely to work equally well on all of them.

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When a Dark Spot Needs a Closer Look

  • —Asymmetric shape, an irregular or blurred border, or more than one color within a single spot
  • —A spot that is growing, changing shape, becoming raised, or bleeding
  • —A new pigment change appearing suddenly rather than building up gradually
  • —Any spot that doesn't fit the pattern of melasma, PIH, or a sunspot and keeps evolving

This article is general health information, not medical advice. It cannot diagnose the cause of any individual's dark spot. A clinician who can examine the skin directly is the right source for that diagnosis and for choosing the right treatment.

References

  1. 1.Sheth VM, Pandya AG (2011). Melasma: a comprehensive update: part I. Journal of the American Academy of Dermatology. PMID 21920241 ✓Melasma develops from an interaction of genetic predisposition, sex hormones, and UV/visible-light exposure, and disproportionately affects women and people with darker skin types.
  2. 2.National Institute of Arthritis and Musculoskeletal and Skin Diseases (2024). Vitiligo. NIH / NIAMS. link ✓Vitiligo is a chronic autoimmune disorder in which melanocytes are destroyed, causing depigmented patches — the pigment-loss counterpart to hyperpigmentation.
  3. 3.Feng H, Berk-Krauss J, Feng PW, Stein JA (2018). Comparison of Dermatologist Density Between Urban and Rural Counties in the United States. JAMA Dermatology. PMID 28296988Dermatologists are geographically concentrated in metropolitan areas, creating access disparities for rural populations seeking an in-person evaluation.

3 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — citations link their sources. Editorial policy

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