Two Types of Dark Patches. Two Completely Different Causes. Two Completely Different Treatments. — Melasma vs PIH Finally Explained

The Wellness Catalyst · Skin Science · Pigmentation Guide India 2026

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Skin Science · Pigmentation Guide India 2026

Two Types of Dark Patches.
Two Completely Different Causes.
Two Completely Different Treatments.
Melasma vs PIH — The Guide That Finally Explains the Difference

I have lost count of how many times I have seen someone spending money on pigmentation treatments that are completely wrong for their specific type of dark patches — because they do not know whether what they have is melasma or post-inflammatory hyperpigmentation. These two conditions share the surface appearance of unwanted skin darkening, but they have entirely different origins, respond to entirely different treatments, and behave in entirely different ways over time. Using a melasma treatment on PIH will produce limited results. Using a PIH approach on melasma will produce frustration. Getting the diagnosis right is the entire foundation of effective treatment.

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The essential distinction Melasma is a chronic hormonal pigmentation condition driven by oestrogen, progesterone, UV, and heat — it appears symmetrically on the face, often follows hormonal events (pregnancy, pill use), and recurs after treatment because the underlying hormonal trigger persists. PIH (post-inflammatory hyperpigmentation) is the skin's inflammatory response to injury — it appears where inflammation occurred, has a specific cause event, fades predictably with time and treatment, and does not recur unless the inflammatory trigger reoccurs. Same appearance on the surface. Completely different biology underneath.

The Indian skin reality: Both melasma and PIH are significantly more prevalent in Indian skin than in lighter skin types — melanocytes in darker skin are more numerous, more reactive, and produce more melanin in response to hormonal and inflammatory stimuli. An estimated 40% of Indian women develop melasma at some point, and virtually every Indian adult with acne develops PIH from those breakouts. Getting the distinction right is not academic — it directly determines what works and what wastes your money.

Understanding Melasma — What It Is and Why It Behaves the Way It Does

Melasma is a chronic, often relapsing pigmentation disorder, primarily driven by hormones and UV radiation acting on melanocytes. The name comes from the Greek word “melas” meaning black — and the condition is characterized by tan to dark brown patches that appear symmetrically on UV-exposed areas of the face, most often the cheeks, upper lip, forehead and chin.

What makes melasma especially problematic — and is what fundamentally distinguishes it from PIH — is that it is not caused by an injury to the skin. It is a systemic disorder in which the melanocytes in certain areas of the face are chronically hyperstimulated by a combination of hormonal stimulation (oestrogen and progesterone receptors are present on melanocytes and when activated stimulate the production of melanin), UV radiation (which further stimulates these sensitised melanocytes), and heat (including infrared radiation, which independently stimulates melanocytes). Melasma is sometimes referred to as the “mask of pregnancy” as it often first appears or worsens during pregnancy when levels of oestrogen and progesterone are at their peak - but it also affects women on combined oral contraceptive pills, women with thyroid dysfunction, and men (yes, men get melasma too - around 10% of melasma patients are male, often with family history).

The recurrence pattern of melasma is one of its most frustrating characteristics. Even after successful treatment — fading the patches with hydroquinone, tranexamic acid, azelaic acid, or chemical peels — melasma almost always returns with any sun exposure or hormonal fluctuation. This is because the treatment addresses the melanin that has already been produced, not the underlying hormonal-UV sensitisation of the melanocytes. The melanocytes in melasma-affected zones remain primed to overproduce melanin. Managing melasma is therefore a long-term commitment to UV protection and hormonal management, not a one-time treatment.

Understanding PIH — What It Is and Why Indian Skin Gets It So Easily

Post-inflammatory hyperpigmentation is the skin's darkening response to any inflammatory event. When the skin experiences inflammation — from acne, a mosquito bite, a rash, friction, a wax burn, an allergic reaction, or even the irritation from a skincare product — keratinocytes in the inflamed zone release mediators (primarily arachidonic acid metabolites and reactive oxygen species) that stimulate adjacent melanocytes to produce excess melanin. This melanin is then transferred to and accumulated in the keratinocytes of the damaged area, creating the dark mark that remains after the original inflammation has resolved.

PIH is not a disease — it is a predictable physiological response to inflammation. In lighter skin types, the melanocyte response to inflammation is less pronounced and PIH marks are lighter and fade faster. In Indian skin — which has more melanocytes per unit area, producing more melanin per inflammatory stimulus — PIH is more severe, darker, and takes longer to fade. This is why the same acne breakout that leaves a light pink mark in a lighter-skinned person leaves a dark brown mark that persists for 6 to 12 months in Indian skin. The underlying biology is the same; the Indian skin's larger melanocyte response simply produces more visible results.

How to Tell the Difference — The 6-Point Diagnostic

Melasma vs PIH — Side by Side

Factor	MELASMA	PIH
Pattern	SYMMETRICAL — both sides of face mirror each other. Both cheeks, both sides of upper lip, forehead center.	ASYMMETRICAL — appears wherever inflammation occurred. One cheek, specific spots, scattered across face.
Cause	Hormonal (oestrogen/progesterone) + UV + heat. No specific skin injury precedes it.	Specific inflammation: acne, waxing, allergic reaction, irritation, injury. There is always a preceding event.
Borders	Irregular, geographic, feathered edges that blend into surrounding skin. Like a "map" pattern.	More defined borders — the mark follows the shape of the original pimple or injury area relatively closely.
Colour	Tan to brown to grey-brown. Can have a bluish-grey cast if deep (dermal melasma).	Pink to red initially (epidermal), progressing to tan-brown as it matures. Rarely grey-brown.
Triggers	Worsens dramatically in summer, pregnancy, on the pill. Fades somewhat in winter then returns.	Worsens with UV exposure (UV darkens existing PIH) but does not follow seasonal hormonal patterns.
Recurrence	HIGH recurrence after treatment — returns with UV or hormonal fluctuation. Maintenance is long-term.	Does NOT recur unless the inflammatory trigger reoccurs. Treat the acne, the PIH does not return.

🔬 The Wood's Lamp Test — What Dermatologists Use

A Wood's lamp (UV-A light) is used by dermatologists to distinguish epidermal (surface) from dermal (deep) pigmentation. Under Wood's lamp: epidermal melanin enhances (appears darker), while dermal melanin does not enhance. This distinction matters for treatment — epidermal PIH and epidermal melasma respond well to topical treatments; dermal melasma (which appears blue-grey in normal light) responds poorly to topicals and may require laser or chemical peel approaches.

At home, a rough test: look at the pigmented patch in direct sunlight vs in dim indoor light. If the patch appears significantly darker in sunlight — it has a strong epidermal component and will respond to topicals. If it appears the same shade or has a greyish cast in both — it may have a dermal component and warrants dermatologist evaluation before investing in topical products.

Treatment — What Works for Each Condition

🔬 Treating MELASMA — The Long Game The foundation — non-negotiable: SPF 50 PA++++ every morning, reapplied every 2 hours outdoors. Iron oxide-containing tinted sunscreen specifically — iron oxides block visible light (HEV) which also stimulates melanocytes. This is not optional for melasma — it is the entire foundation of management. Every treatment product works better and longer when UV and visible light are blocked. Without SPF, nothing else works for melasma. First-line topicals (dermatologist-proven): → Tranexamic acid 2–5% (blocks plasmin-melanocyte stimulation pathway) → Azelaic acid 15–20% (mild tyrosinase inhibitor + anti-inflammatory) → Niacinamide 10% (blocks melanin transfer to keratinocytes) → Kojic acid 2% (copper chelation inhibits tyrosinase — but watch for irritation) Prescription options (dermatologist-managed): → Hydroquinone 2–4%: gold standard, but max 3–4 months continuous use → Tretinoin: accelerates cell turnover, removes pigmented cells → Combination formulas (Tri-Luma: hydroquinone + tretinoin + steroid) → Oral tranexamic acid (250mg twice daily): prescription, for refractory cases Address the hormonal driver: If melasma worsened on the combined pill — discuss switching to a progesterone-only pill or non-hormonal contraception with your gynaecologist. Treating melasma while on oestrogen-containing contraception is fighting the cause with treatment simultaneously.

🔬 Treating PIH — Address the Root First The most important PIH principle: Stop the source of inflammation first. If acne is producing PIH every month — the PIH treatment is addressing marks that are being continuously replenished. Treating PIH without treating the acne is futile. Fix the cause, then fade the marks. First-line topicals for PIH: → Niacinamide 10%: the safest, most consistent PIH treatment — blocks melanin transfer → Vitamin C 10–20%: antioxidant + tyrosinase inhibition — morning use with SPF → AHAs (glycolic/lactic): accelerate cell renewal to replace pigmented keratinocytes → Tranexamic acid 2–5%: addresses the plasmin-PIH pathway specifically The timeline reality for Indian PIH: Superficial (epidermal) PIH in Indian skin takes 6 to 12 months to fade with consistent treatment + SPF. Deep (post-cystic) PIH can take 12 to 24 months. These are realistic, evidence-based timelines — not failures of treatment. The pace of fading is limited by the 28-day cell renewal cycle and the depth of melanin deposition. SPF for PIH: Essential — UV darkens existing PIH by stimulating the melanocytes in the affected area. Every missed SPF day can set back PIH fading by 2 to 3 weeks of treatment time. SPF is not optional for PIH — it is as important as the brightening actives. For the complete SPF guide, see our SPF Reapplication India guide.

🔬 Related Reading:

→ Tranexamic Acid for Indian Skin

→ Niacinamide vs Vitamin C Guide

→ SPF Reapplication India Guide

The Mistakes That Keep Indian Pigmentation From Fading

❌ Using the same treatment for both Hydroquinone is often prescribed for all pigmentation regardless of type. For PIH — it works but so do safer alternatives. For melasma — it works but recurs when stopped. For dark elbows and knees (friction PIH) — it works slowly. The point is: know what you are treating, because some treatments (particularly lasers) can worsen PIH in Indian skin while being appropriate for melasma, and vice versa.

❌ Giving up before the timeline completes Both melasma and PIH require minimum 8 to 12 weeks of consistent treatment before significant results are visible — and Indian skin PIH may require 6 to 12 months. Stopping at 4 to 6 weeks because "nothing is happening" is the most common reason pigmentation treatment fails. The cell turnover cycle is 28 days — meaningful improvement requires multiple complete cycles of consistently maintained treatment.

❌ Treating melasma with heat-based procedures Infrared heat from some laser treatments and certain facial devices stimulates melanocytes independently of UV — and for melasma specifically, heat is a trigger. Some laser treatments that work well for PIH can paradoxically worsen melasma by activating the heat-sensitive melanocytes in melasma zones. Always specify to your dermatologist that you have melasma before any device-based treatment, and request cooling protocols.

❌ Assuming summer tan and melasma are the same Many Indian women assume their melasma is just tanning and will reverse with de-tan treatments. Tanning is a diffuse darkening across all UV-exposed skin. Melasma is a patterned, symmetrical darkening in specific zones that is hormonally driven and does not respond to de-tan products. De-tan treatments may temporarily brighten the surface but cannot address the hormonal melanocyte hyperactivation that drives melasma — and the improvement reverses rapidly without sustained UV protection and specific treatment.

Realistic Timelines — For Both Conditions

Week 4–6 🌱 Surface brightness improving. Recent PIH marks slightly lighter. Melasma density slightly reduced at edges.

Month 3 ✨ Visible improvement in recent PIH. Melasma patches lighter but still present. Consistent treatment essential — do not stop here.

Month 6 🌸 Most recent PIH significantly faded. Old, deep PIH continuing. Melasma substantially reduced with consistent SPF + treatment.

Month 12+ 💎 Deep PIH substantially faded. Melasma well-managed with maintenance. Even skin tone achieved through consistency, not luck.

The Evidence-Based Pigmentation Stack

✨ Tranexamic Acid 2–5% Works for BOTH melasma and PIH. Blocks plasmin-melanocyte signalling. Morning + evening. Shop Now →

🌟 Niacinamide 10% Works for BOTH. Melanin transfer blocker. Most consistent PIH treatment. Pair with TXA for maximum effect. Shop Now →

☀️ Tinted SPF 50 PA++++ Iron oxide tint blocks visible light (HEV) — essential for melasma management that mineral-only SPF misses. Shop Now →

Affiliate links — supports The Wellness Catalyst 🙏

Pigmentation Questions Answered

Can melasma be permanently cured? No — melasma can be managed very effectively, often to the point of invisibility, but the underlying hormonal-UV sensitisation of the affected melanocytes remains. If the triggering factors (hormones, UV) are not controlled, melasma returns. This is why permanent SPF use and long-term maintenance with topical actives is the realistic management strategy — not a course of treatment followed by stopping. Women whose melasma appeared only during pregnancy may find that it resolves after delivery and does not return if UV is well-protected — but those with melasma unrelated to pregnancy typically need ongoing management.

I have been told I have melasma but my patches are not symmetrical — is this possible? Yes — melasma is predominantly symmetrical but not always perfectly so. Mixed presentations exist where melasma is the primary diagnosis but UV exposure is asymmetric (driving-side cheek more affected) or where melasma and PIH co-exist on the same face. In these cases, a dermatologist's evaluation with Wood's lamp is particularly valuable to identify which zones are melasma and which are PIH, allowing targeted treatment of each component. Treating both as one condition invariably underfocuses on one of them.

Is de-tan treatment at a salon useful for melasma or PIH? For PIH, mild chemical exfoliation de-tan treatments (lactic or glycolic acid-based) can accelerate PIH fading by increasing cell turnover, with results visible over multiple sessions. For melasma, most salon de-tan treatments provide only superficial brightening that reverses quickly because they do not address hormonal melanocyte activation. Many salon treatments also use heat (steam, warm massage), which is counterproductive for melasma. The most effective de-tan for pigmentation is a correctly prescribed topical routine used consistently at home, not a monthly salon treatment.

Can dark elbows, knees, and inner thighs be treated the same way? Dark elbows, knees, and inner thighs are almost always PIH from chronic friction and pressure — not melasma. The treatment approach is: remove friction (exfoliation to clear dead cell buildup), apply niacinamide + urea (for hyperpigmentation + keratolytic effect in these thicker-skin areas), and use SPF on any sun-exposed dark patches. The skin in these areas is thicker than facial skin, so penetration of actives is lower and timelines longer. Consistent gentle exfoliation + niacinamide + hydration produces the best results for these body PIH zones.

⚠️ Note

This guide is for educational purposes. Accurate diagnosis of melasma vs PIH vs other pigmentation disorders (seborrhoeic keratosis, solar lentigo, lichen planus pigmentosus) requires dermatological evaluation. Prescription treatments including hydroquinone and tretinoin require physician supervision. The author holds an M.Pharm in Pharmaceutics.

✦   same appearance. completely different biology. completely different treatment.   ✦

You Cannot Treat Melasma
With a PIH Protocol
And Wonder Why It Keeps Coming Back.

The dark patches have the same surface appearance. But melasma is a systemic hormonal condition that requires UV control, hormonal management, and long-term maintenance. PIH is an inflammatory response that requires treating the inflammation source, fading the mark, and preventing UV from darkening it further. The products that work for one partially work for the other — but without the complete approach specific to each condition, results are always partial. Diagnose first. Treat specifically. Then stay consistent for the months it actually takes.

🔬 Do you have melasma, PIH, or both? Tell me your pattern below!

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