Derm Cases · Dermatology / Pigmentary disorders / Skin of colour
OSCE — dark marks after acne: PIH depth, therapy, and ochronosis risk
An 8-minute OSCE station on post-inflammatory hyperpigmentation after acne in skin of colour, epidermal vs dermal depth, photoprotection and topical stepwise therapy, and hydroquinone/exogenous ochronosis safety.
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Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on post-inflammatory hyperpigmentation after acne in skin of colour, epidermal vs dermal depth, photoprotection and topical stepwise therapy, and hydroquinone/exogenous ochronosis safety.
Brief (to candidate)
A 24-year-old woman with Fitzpatrick V skin has resolved facial acne but persistent brown macules at prior inflammatory sites for 8 months. She has been using over-the-counter hydroquinone daily for 10 months. You have 8 minutes to diagnose PIH, plan depth-aware therapy, and stop unsafe hydroquinone use.
Candidate instructions
- Define PIH and link it to prior inflammation in skin of colour.
- Contrast epidermal vs dermal PIH clinically.
- Prioritise control of the driver disease + photoprotection.
- Outline evidence-based topical options and timelines.
- Recognise exogenous ochronosis risk from prolonged hydroquinone.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Definition | Acquired excess melanin after inflammation/injury (acne, eczema, procedures); more severe/persistent in Fitzpatrick IV–VI[4][5] |
| Depth typing | Epidermal (tan-brown, often Wood's accentuation, better topical response) vs dermal/mixed (grey-brown, slower, may need procedural care carefully)[2][5] |
| Core principles | Treat active inflammation first (acne control); strict broad-spectrum photoprotection including visible light considerations in SOC; set 3–6+ month expectations[1][4] |
| Therapeutics | Topical hydroquinone (time-limited), retinoids, azelaic acid, chemical peels/selected energy devices for refractory disease — choose stepwise to minimise further inflammation-induced pigment[1][2][3] |
| Ochronosis | Continuous HQ >6 months ± confetti blue-black darkening → stop HQ, reassess diagnosis, switch agents; do not escalate HQ dose blindly |
| Differential | Melasma, drug pigmentation, Addison (systemic signs), fixed drug eruption residual pigment — do not label everything PIH |
| Communication | Reassure benign nature; avoid aggressive lasers that worsen PIH in SOC without expertise |
Model key actions
- Diagnose acne-induced PIH in skin of colour and continue acne control + SPF.[4]
- Stop prolonged unsupervised hydroquinone and redesign a safer regimen.[1][2]
- Counsel slow improvement and reassess if no gain by 6–12 months.
Common errors
- Using hydroquinone indefinitely without ochronosis counselling.
- Aggressive peels/lasers that trigger more PIH.
- Treating pigment while ignoring active acne.
- Missing systemic hyperpigmentation mimics (Addison).
References5ShowHide
- [1]Mar K, Khalid B, Maazi M, et al. Treatment of Post-Inflammatory Hyperpigmentation in Skin of Colour: A Systematic Review. Journal of cutaneous medicine and surgery, 2024.PMID 39075672
- [2]Shenoy A, Madan R. Post-Inflammatory Hyperpigmentation: A Review of Treatment Strategies. Journal of drugs in dermatology : JDD, 2020.PMID 32845587
- [3]Kashetsky N, Feschuk A, Pratt ME, et al. Post-inflammatory hyperpigmentation: A systematic review of treatment outcomes. Journal of the European Academy of Dermatology and Venereology, 2024.PMID 37843491
- [4]Elbuluk N, Grimes P, Chien A, et al. The Pathogenesis and Management of Acne-Induced Post-inflammatory Hyperpigmentation. American Journal of Clinical Dermatology, 2021.PMID 34468934
- [5]Maghfour J, Olayinka J, Hamzavi IH, et al. A Focused review on the pathophysiology of post-inflammatory hyperpigmentation. Pigment cell & melanoma research, 2022.PMID 35306737