Post-inflammatory hyperpigmentation (PIH) is increased skin pigmentation that develops after inflammation or injury to the skin.
PIH occurs when inflammation alters melanin production or distribution within the skin. It is particularly common after inflammatory acne and can occur in people of any skin color, although it is often more noticeable and persistent in darker skin.
PIH is a change in pigmentation rather than a true scar. It may gradually fade over time, although some cases persist for months or longer.
QUICK FACT
A flat dark mark left after a pimple has healed may be PIH rather than an acne scar. The distinction matters because the two involve different underlying changes.
COMMONLY CONFUSED WITH
- Acne scar: structural alteration of the skin caused by tissue damage and abnormal healing.
- Post-inflammatory erythema: persistent redness following inflammation rather than increased pigmentation.
SEE ALSO