Post-Inflammatory Hyperpigmentation (PIH): Why Dark Marks Linger And What Can Help
Written by Dr. Maha Shariff · May 28, 2026 · Post Inflammatory Hyperpigmentation
Post-Inflammatory Hyperpigmentation (PIH): Why dark marks linger after breakouts, eczema, or friction, and evidence-based treatments that actually help.
Post-Inflammatory Hyperpigmentation (PIH): Why Dark Marks Linger And What Can Help
Post-inflammatory hyperpigmentation (PIH) is a common pigment related concern seen in dermatology and aesthetic practice. It refers to flat brown, grey or sometimes purplish marks that remain on the skin after inflammation has settled. It can follow acne, eczema, dermatitis, insect bites or minor trauma such as picking or friction.
Importantly, PIH is not a scar. It reflects altered pigment production rather than structural damage to the skin. It occurs when inflammation stimulates melanocytes (pigment producing cells) to produce excess melanin during the healing process.
PIH is seen across all skin types but tends to be more persistent in medium to deeper skin tones due to increased melanocyte reactivity.
Flat pigmentation marks (PIH) left after active breakouts have cleared
Why PIH develops and why it can persist
PIH can last from weeks to several months depending on the depth of pigment within the skin. Following inflammation, melanocytes increase melanin production. This pigment may be confined to the epidermis (more superficial and faster to resolve) or extend into the dermis (deeper and more persistent).
Key factors that commonly prolong PIH include:
- Ongoing inflammation (e.g. active acne, eczema, repeated picking)
- UV and visible light exposure, both of which can darken existing pigmentation
Common causes of post-inflammatory hyperpigmentation
PIH can result from any inflammatory process, including:
- Acne, particularly inflamed or irritated lesions that have been picked
- Eczema and dermatitis
- Folliculitis
- Insect bites
- Friction, repeated rubbing or pressure over the affected area(s)
It is important to distinguish PIH from acne scarring. PIH is pigmentary and potentially reversible, whereas scarring involves permanent structural change in the skin.
Approach to managing PIH
Management of PIH is gradual and relies on consistency rather than intensity. Dermatology-led care is typically based on three core principles:
Core management principles:
- 1. Treat the underlying cause of inflammation: If acne or eczema is ongoing, new pigmentation will continue to form. Controlling the underlying condition is essential before focusing on pigment reduction.
- 2. Daily sun protection (including tinted SPF): Sun exposure is one of the most significant factors in persistent pigmentation. A broad-spectrum SPF 50 should be used daily. In pigment-prone skin, tinted sunscreens provide additional benefit by offering protection against visible light.
- 3. Evidence-based topical treatments: Topical skincare remains the foundation of treatment. Improvement is gradual and typically seen over 8-12 weeks.
Evidence-based topical treatments for PIH
Selected active ingredients:
- Cysteamine: Evidence-supported depigmenting agent used in specialist regimens
- Retinoids: Support epidermal turnover and gradual pigment clearance
- Azelaic acid: Anti-inflammatory and pigment-modulating, particularly useful in acne-related PIH
- 4-n-butylresorcinol: Targeted tyrosinase inhibitor used in resistant pigmentation
- Hydroquinone (short-term, medically supervised only): Can be effective but requires careful time limited use
- Niacinamide: Supports barrier function and reduces pigment transfer
- Topical tranexamic acid: Used in selected cases of persistent or mixed pigmentation
- Vitamin C: Antioxidant that helps reduce oxidative stress involved in pigment formation
Treatment should always be individualised based on skin type, sensitivity, and underlying triggers.
In-clinic treatments for post-inflammatory hyperpigmentation
For more persistent PIH, selected procedures include:
- Chemical peels - selected based on skin tone and barrier status
- Microneedling - may support overall skin quality and enhance delivery of topical actives
- Skin boosters - improve hydration and dermal quality, supporting overall skin tone and texture
At Dr Maha Aesthetics, treatment planning is individualised and skin-first. In many cases, the skin benefits from a preparatory phase before procedural treatments are introduced.
Laser treatment for pigmentation
Laser may be considered in selected cases of pigmentation. However, it is not suitable for all skin types and may carry a risk of worsening pigmentation if not carefully selected and performed. Laser treatments are not offered at Dr Maha Aesthetics but may be discussed to support patient understanding of available options.
Expected timeline for PIH to fade
Superficial PIH may begin to improve within 8-12 weeks with consistent treatment and sun protection. Deeper pigmentation may take several months or longer and often requires a combination of approaches. Progress is gradual, and consistency is the most important factor.
When to seek professional help for hyperpigmentation
A dermatology-led assessment may be helpful if:
- Pigmentation has not improved after 2-3 months of consistent skincare
- You are unsure whether it is PIH, melasma or another pigmentary condition
- Acne or eczema remains active
- You have medium to deeper skin tones requiring a tailored approach
- You are considering clinic-based treatments
Summary
Post-inflammatory hyperpigmentation is a common and generally manageable skin concern that occurs following inflammation. It is driven by increased melanin production and may be prolonged by ongoing inflammation and sun exposure.
The core principles of management include: controlling underlying inflammation, consistent daily sun protection, and regular use of evidence-based topical treatments. With a structured and individualised approach, gradual improvement can be achieved.
Hyperpigmentation Consultation
If you are struggling with persistent pigmentation or are unsure whether your skin changes are due to PIH or another condition, a skin focused consultation can help clarify the diagnosis and guide a tailored treatment plan.
- Accurate pigmentary diagnostics
- Evidence-based ingredient selection
- Safe procedural integration
References
- 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.
- Callender VD, St Surin-Lord S, Davis EC, Maclin M. Postinflammatory hyperpigmentation: etiologic and therapeutic considerations. American Journal of Clinical Dermatology. 2011.
- Taylor SC, Cook-Bolden F, Rahman Z, Strachan D. Acne vulgaris in skin of color. Journal of the American Academy of Dermatology. 2002.
- Passeron T, Lim HW, Goh CL, et al. Photoprotection according to skin phototype and dermatoses: a review. Journal of the American Academy of Dermatology. 2022.
- Kang HY, Ortonne JP. The role of visible light in pigmentary disorders: a review. Journal of the European Academy of Dermatology and Venereology. 2010.