PIH is an acronym for Post-Inflammatory Hyperpigmentation. Post-inflammatory means “after inflammation.” Hyperpigmentation means “increased pigmentation,” or a darkening of the skin. So post-inflammatory hyperpigmentation, or PIH, is the discoloration or darkening of the skin that develops after an inflammatory wound.
PIH spots are darker than the surrounding skin tissue, and can vary in color from pink to red, purple, or brown. More »