Post inflammatory erythema (PIE) represents one of the most common sequelae following acne resolution, characterized by persistent red or pink discoloration at sites of previous inflammatory lesions. This comprehensive guide examines the pathophysiology, clinical presentation, diagnostic criteria, and evidence-based management approaches for PIE, with particular focus on acne-related cases. Understanding Post Inflammatory Erythema (PIE) What is Post Inflammatory Erythema? Pos