What is Post-Inflammatory Hyperpigmentation (PIH)?

PIH is the brown/reddish discoloration left on skin after inflammation (acne, picking, irritation, burns). Distinct from melasma — triggered by inflammation, not hormones. Fades naturally over 6–18 months; can be accelerated with: tranexamic acid, azelaic acid, vitamin C, niacinamide, kojic acid, alpha arbutin. Most common in Fitzpatrick III–VI skin tones. Daily SPF is non-negotiable for PIH to actually fade rather than deepen.