Pigmentation
Post-Inflammatory Hyperpigmentation
Post-inflammatory hyperpigmentation (PIH) is the flat brown or dark mark left after acne, eczema, burns or procedures. It is not a true scar and usually fades, and a dermatologist can speed this up with topical lighteners, gentle peels and conservative laser.
Overview
PIH is common in Asian and darker skin types. The key is to stop the inflammation that causes it, then lighten what remains.
Red marks after acne (post-inflammatory erythema) look similar but need vascular treatment instead.
At a glance
Treatment options
Azelaic acid, retinoids, niacinamide, tranexamic acid, light chemical peels and low-fluence laser.
Timeline
Untreated PIH can take 6 to 12 months to fade; treatment often shortens this.
Prevention
Treat acne early, avoid picking and use daily sunscreen.
Frequently asked questions
Are acne marks the same as acne scars?
No. Flat marks are pigment or redness changes; scars are changes in skin texture.
Will PIH go away on its own?
Usually, but slowly. Sun exposure can keep it dark.
Can lasers make PIH worse?
Aggressive settings can, which is why specialist judgement matters.
Related
Choose a specialist
See a board-certified dermatologist, not just a “skin clinic”
In Korea, only about 1 in 10 clinics that treat skin is run by a dermatology specialist (피부과 전문의). Specialists complete a four-year dermatology residency and a national exam. Our directory lists only clinics in the Association of Korean Dermatologists’ specialist search. This page is general information, not medical advice.