Post-Inflammatory Hyperpigmentation (PIH) Adult Non-Prescription Cosmetic Skincare Guide

Disclaimer (Adults, Non-Prescription Only)

This policy provides general cosmetic-class information for adults (18+) and does not diagnose, treat, prevent or cure post-inflammatory hyperpigmentation (PIH) or any medical skin condition ¹ ⁴. PIH can resemble other pigment disorders, including melasma and, in some cases, more serious lesions, so diagnosis must always remain with a general practitioner (GP) or dermatologist ¹ ². Cosmetic practitioners must limit their role to appearance support using non-prescription skincare and must not make therapeutic claims or manage prescription treatments ² ³.

1. Purpose & Scope

The purpose of this policy is to give adults with PIH a clear, safe, non-prescription framework to support the appearance of dark marks using gentle skincare, sun protection and irritation avoidance ¹ ⁴. It applies to cosmetic-class skincare advice only and does not cover prescription therapies, medical procedures or systemic treatments ² ³. The policy is intended for use in cosmetic settings and patient education, with all medical diagnosis and treatment remaining the responsibility of registered medical practitioners ² ³.

2. What Is Post-Inflammatory Hyperpigmentation (PIH)?

2.1 Definition

PIH appears as flat brown, dark brown, or grey-brown marks that show up after inflammation or irritation, such as acne, eczema flares, injuries or cosmetic procedures ¹ ⁴. These marks occur because melanocytes release extra pigment (melanin) during the healing process, which is then deposited in the upper layers of the skin ¹ ⁴. Even once the skin has healed, the pigment can remain for many months and sometimes longer without strict sun protection and trigger control ¹ ⁴.

2.2 Who Gets PIH More Easily?

Medium-to-darker Fitzpatrick skin types develop deeper and longer-lasting PIH because their pigment cells are naturally more reactive and produce more melanin in response to inflammation ¹ ⁴. Even small triggers like pimples, bug bites, friction or scratches can leave dark marks in these skin types ¹. This higher sensitivity means PIH-prone and darker skin types require gentler routines and stronger sun protection to keep pigment stable ² ⁷.

3. Common Causes & Triggers

3.1 Acne & Blemishes

3.1.1 How Acne Creates PIH

When acne becomes inflamed, pigment cells release melanin into the surrounding tissue, leaving dark marks that last long after the spot heals ¹ ⁴. Picking, squeezing or scrubbing the area makes the pigmentation significantly worse by deepening the inflammation and spreading pigment further into the skin ¹ ⁴. This is why acne-prone skin often has clusters of dark marks even when active acne is mild or intermittent ¹.

3.1.2 Prevention Tip

Avoid touching or manipulating acne lesions because this drives pigment deeper and increases the risk of PIH ¹ ⁴. Gentle, non-irritating routines help reduce inflammation and lower PIH risk over time ¹. If acne is persistent or scarring, early medical management with a GP or dermatologist helps prevent long-term PIH cycles ² ³.

3.2 Skin Irritation

3.2.1 Why Irritation Causes Pigment

Harsh skincare products such as strong acids, scrubs, fragranced products and aggressive retinoids damage the skin barrier and trigger inflammation, which activates pigment cells ¹ ⁴. This inflammatory response leads to dark spots that often last longer than the irritation itself, particularly in PIH-prone or darker skin types ¹ ⁴. The stronger or more frequent the irritation, the deeper and more stubborn the PIH becomes.

3.2.2 Avoiding Irritation

PIH-prone individuals should avoid scrubs, strong acids, fragrances and abrasive cleansers, especially when used frequently or in combination ¹ ⁴. Gentle, fragrance-free skincare protects the barrier and lowers pigment activation, improving long-term outcomes ¹. The calmer and more resilient the skin, the less PIH develops in response to everyday triggers.

3.3 Cosmetic Procedures

3.3.1 How Procedures Trigger PIH

Lasers, IPL, microneedling and peels create controlled injury to the skin, which can produce PIH if the skin is reactive or if parameters are too aggressive ⁴ ⁷. Darker skin types (Fitzpatrick III–VI) are more sensitive to these procedures and have a higher risk of PIH when exposed to excess heat or inflammation ⁴ ⁷. Heat from devices can also activate pigment immediately after treatment and in the days that follow, particularly if sun protection and aftercare are inadequate ⁴ ⁷.

3.3.2 Prevention Strategy

Use conservative device settings, always perform test spots in higher-risk patients and avoid treating recently tanned or sunburned skin ⁴ ⁷. Strict sunscreen use and avoidance of sun and solarium exposure for weeks before and after treatment reduce PIH risk significantly ⁵ ⁶. Patients must follow all post-care instructions, including avoidance of heat, friction, picking and harsh products, to minimise post-procedure pigmentation changes ⁴ ⁷.

3.4 Heat & Sun Exposure

3.4.1 Sunlight as a Major Driver

Ultraviolet (UV) and visible light darken PIH quickly, even through windows or on cloudy days, by repeatedly activating pigment cells ¹ ⁴ ⁵. Every day without adequate SPF deepens the pigment and resets fading progress, which is why PIH often appears “stuck” when sunscreen habits are inconsistent ¹ ⁵. In Australian conditions, UV levels frequently exceed recommended thresholds, making daily photoprotection essential even for darker skin types ⁵ ⁶ ⁸.

3.4.2 Heat Exposure

Heat from hot showers, workouts, cooking steam, saunas and warm weather increases local inflammation and pigment activation in PIH-prone skin ¹ ⁴ ⁷. In susceptible individuals, heat alone can darken marks almost as much as direct sunlight, especially when combined with UV exposure ⁴ ⁷. Reducing heat exposure to the face helps stabilise pigment and improves cosmetic outcomes over time.

4. How PIH Behaves Over Time

4.1 Natural Fading Timeframe

PIH often fades over many months and may persist longer, especially in darker skin types ¹ ⁴. The time course depends on skin tone, inflammation depth and sun exposure patterns ¹. Consistency with gentle routines, trigger avoidance and sunscreen is critical to fading and to preventing new marks from forming ¹ ⁵.

4.2 Why PIH Seems “Stuck”

PIH does not fade if it is being reactivated every day by sunlight, visible light, heat or irritation ¹ ⁴ ⁵. Even an excellent skincare routine cannot overcome poor photoprotection or repeated barrier damage. Keeping the skin calm, moisturised and well protected from UV and heat is the only way PIH can fade predictably over time ¹ ⁵ ⁷.

5. Daily Cosmetic Routine for PIH-Prone Skin

5.1 Morning Routine

5.1.1 Cleanse Gently

Use a gentle, fragrance-free cleanser to avoid stripping the skin and disrupting the barrier. Scrubs, brushes and harsh foaming cleansers can irritate PIH-prone skin and worsen pigmentation ¹ ⁴. A calm, intact barrier improves how well the rest of the routine works and reduces the risk of new marks forming ¹.

5.1.2 Vitamin C

Vitamin C helps support protection against environmental stress and brightens uneven tone, providing a more radiant appearance ⁴. It works best when used in the morning underneath sunscreen so that it can act as an antioxidant during light exposure ⁴. Regular, long-term use improves perceived radiance and reduces the look of dullness associated with PIH.

5.1.3 Niacinamide

Niacinamide strengthens the barrier and helps calm visible redness and blotchiness, which often accompany PIH ⁴. It supports a more even-looking complexion in PIH-prone skin by reducing inflammation and improving barrier function ⁴. Its anti-inflammatory benefits reduce irritation-driven pigment and improve tolerance to other skincare products.

5.1.4 Ceramide Moisturiser

Ceramides restore and maintain the skin barrier and improve comfort throughout the day ⁴. A healthier barrier reduces the risk of irritation from other products and environmental stressors. Good moisture retention improves skin resilience and decreases the likelihood of pigment flares when the skin is exposed to minor insults.

5.1.5 SPF50+ (Critical Step)

Tinted mineral SPF50+ protects against UVA, UVB and, with iron oxides, visible light — the main drivers of PIH darkening ⁴ ⁵ ⁷. Without SPF, dark marks deepen every day regardless of how good the rest of the skincare routine is ¹ ⁵. This is generally the most important step for PIH-prone skin and should be used daily in Australian conditions whenever the UV index is 3 or above ⁵ ⁶.

5.2 Evening Routine

5.2.1 Gentle Cleansing

Remove sunscreen, oil and impurities with a mild, non-stripping cleanser at night. Avoid products that sting, dry out or visibly irritate the skin, as these will worsen PIH ¹ ⁴. A gentle cleanse sets the stage for brightening products to work safely and effectively over time.

5.2.2 ONE Brightening Serum

Use only one brightening active at night to prevent irritation; good options include cosmetic-strength azelaic acid ≤10%, topical tranexamic acid ≤3%, arbutin or liquorice extract ⁴. Combining multiple strong actives often inflames the skin and worsens PIH rather than improving it ⁴ ⁷. Simple, well-tolerated routines generally outperform complex regimens in PIH-prone skin.

5.2.3 Barrier Repair Overnight

Finish with a ceramide-rich moisturiser to protect and repair the barrier overnight ⁴. Overnight restoration reduces inflammation, supports natural healing and helps pigment gradually settle. Strong, resilient barriers mean fewer future dark marks from everyday insults.

5.3 Weekly Add-Ons

5.3.1 Gentle Exfoliation (Optional)

Use mild PHA or lactic acid once weekly if your skin is stable and comfortable. Over-exfoliation inflames the skin and deepens PIH, especially in darker skin types ¹ ⁴. Stop immediately if you experience redness, stinging or sensitivity, and revert to a simple barrier-repair routine.

5.3.2 Cosmetic LED (Optional)

LED can support improved radiance and reduce visible redness without generating heat or inflammation when used appropriately ⁴. It is generally safe for PIH-prone skin as a supportive cosmetic treatment. LED should complement, not replace, daily sunscreen and a gentle skincare routine.

5.3.3 Only If Skin Is Stable

Weekly extras should only be added if the basic routine is irritation-free for several weeks. Adding too many products or treatments at once increases the risk of inflammation and PIH flares. The calmer and more stable the skin, the better PIH behaves over the long term.

6. What Helps the Appearance of PIH

6.1 Sunscreen as the Foundation

Sunscreen prevents daily darkening and allows natural fading of PIH by blocking UV and, with tinted formulas, some visible light ⁴ ⁵. It is more important for PIH than any brightening serum or cosmetic procedure. Without SPF, no skincare routine will work effectively because the underlying trigger is never controlled ¹ ⁵.

6.2 Camouflage Makeup

Camouflage makeup reduces visual contrast between PIH and the surrounding skin, improving day-to-day appearance and confidence ¹ ⁴. Mineral or non-comedogenic products are ideal for PIH-prone skin because they are less likely to irritate or clog pores. Makeup is a valid cosmetic tool and can be used alongside all other appearance-supporting measures ¹ ².

6.3 Gentle Brighteners

Non-prescription brighteners can help PIH appear lighter when used consistently over weeks to months ⁴. They work best when irritation is avoided and when always paired with sunscreen. In most cases, consistency and tolerance matter far more than the strength of the product ⁴ ⁷.

7. What Makes PIH Worse

7.1 Irritation & Over-Exfoliation

Harsh skincare damages the barrier and triggers more pigment production in PIH-prone skin ¹ ⁴. Strong acids, aggressive scrubs, dermarollers and overuse of actives all worsen PIH, particularly in darker skin types. Keeping routines simple, gentle and fragrance-free helps prevent flare-ups.

7.2 Picking & Squeezing

Picking or squeezing blemishes creates deeper inflammation and darker PIH compared with lesions that are left alone ¹ ⁴. Even small blemishes can become large, long-lasting marks when manipulated. Avoid touching, squeezing or scratching acne and other lesions wherever possible.

7.3 Whitening Creams

Unregulated whitening creams purchased online or overseas often contain potent steroids, hydroquinone or mercury, which can permanently damage pigmentation pathways and overall skin health ¹ ⁵. These products are unsafe, may cause severe irritation and rebound darkening, and must never be used without medical supervision. Patients using such products should be encouraged to stop and seek medical advice ¹ ³.

8. When to See a GP or Dermatologist

8.1 Medical Red Flags

Seek medical review for any pigmentation that is new, rapidly changing or irregular in shape or colour ¹ ². Raised, bleeding, crusting or symptomatic marks (such as itching or pain) require urgent assessment because they may not be PIH at all ¹ ². In these cases, only a GP or dermatologist can safely distinguish PIH from other serious conditions, including skin cancers.

8.2 When Cosmetic Care Isn’t Enough

If PIH does not improve after 12 weeks of strict SPF use and gentle skincare, medical advice is recommended ¹ ². A dermatologist can confirm the diagnosis, assess for underlying drivers and review prescription or procedural options if appropriate ² ⁴. Some pigment conditions require medical-grade treatments or combination approaches that fall outside cosmetic scope ² ³ ⁷.

9. Q&A — Post-Inflammatory Hyperpigmentation

Q1: Why do dark marks stay after a pimple heals?

PIH occurs when inflammation triggers pigment release that remains in the skin long after the blemish heals ¹ ⁴. It fades slowly and darkens easily with sunlight exposure if SPF is not used ¹ ⁵.

Q2: Is PIH permanent?

PIH is not permanent, but it can take many months to fade, especially in medium-to-darker skin tones ¹ ⁴. Strict sun protection and avoiding irritation are essential for improvement ¹ ⁵.

Q3: Does sunscreen lighten PIH?

Sunscreen does not bleach PIH, but it prevents the mark from getting darker and allows the skin to naturally fade the pigment over time ⁴ ⁵. Without SPF50+, PIH is reactivated daily by UV and visible light, making it very difficult to lighten ⁵ ⁶.

Q4: What brightening ingredients help PIH?

Niacinamide, vitamin C, azelaic acid ≤10%, TXA ≤3% and arbutin can help soften the appearance of dark marks when used consistently ⁴. They work best when only one or two are used at a time and always combined with sunscreen ⁴ ⁵.

Q5: Why does PIH get worse in summer?

UV rays, visible light and heat are stronger in summer and activate pigment cells more easily, especially in darker skin types ¹ ⁵. Even short outdoor exposure—such as driving or walking outside—can deepen PIH rapidly if sunscreen is not applied ⁵ ⁶.

Q6: Can exfoliation speed PIH fading?

Gentle exfoliation with mild acids may help brighten the skin, but strong or frequent exfoliation causes irritation that makes PIH worse ¹ ⁴. PIH-prone skin does best with light, infrequent exfoliation and a calm, well-hydrated barrier ¹ ⁴.

Q7: Why is PIH more common in darker skin?

Darker skin has more active melanocytes that produce pigment quickly when irritated or inflamed ¹ ⁴. This natural response leads to deeper and longer-lasting PIH after even mild triggers ¹ ⁷.

Q8: Is PIH the same as a scar?

No—PIH is just pigment in the skin, while scars involve changes in texture or collagen ¹ ⁴. PIH generally fades with time and sun protection, whereas scars often require different treatments ¹ ⁴.

Q9: Why did my PIH get worse after strong products?

Strong actives can inflame the skin and damage the barrier, causing pigment cells to become more active and darken PIH ¹ ⁴. Many people improve when they simplify their routine, protect the barrier and stop the products causing stinging, peeling or redness ¹ ⁴.

Q10: When should I see a dermatologist?

You should see a dermatologist if pigmentation is new, changing, raised, irregular or not improving after 12 weeks of careful routine and sun protection ¹ ². Some pigment conditions are not PIH at all and require medical assessment for safety ¹ ².

Sources

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Disclaimer for Newcastle Cosmetic Doctor Policies & Procedures

The policies and procedures contained within this document are the exclusive property of Newcastle Cosmetic Doctor and are provided for internal clinical governance and educational purposes only. These materials represent the internal operational framework, safety standards, and evidence-based protocols developed and implemented by Dr. Bart John Scanlon and the Newcastle Cosmetic Doctor team. They are designed specifically for use within Newcastle Cosmetic Doctor and reflect our clinic’s own professional standards, risk assessments, and compliance obligations under Australian law and regulatory authorities. External individuals, practitioners, or organisations must not copy, reproduce, distribute, or rely upon these materials, in whole or in part, for their own clinical, commercial, or educational use without prior written consent from Newcastle Cosmetic Doctor. These materials do not constitute medical, legal, or professional advice and are not intended to be adopted as official protocols or procedures by any other entity. Any external use or adaptation must be independently reviewed and modified to meet the relevant laws, guidelines, and standards applicable to the user’s own jurisdiction, scope of practice, and facility operations. Newcastle Cosmetic Doctor and Dr. Bart Scanlon accept no liability for any loss, injury, or damage arising from the unauthorised use, reliance upon, or misinterpretation of this material.