Reliability assessment and validation of the postacne hyperpigmentation index (PAHPI), a new instrument to measure postinflammatory hyperpigmentation from acne vulgaris

The PAHPI shows good reliability and validity when scored on patients with PIH from acne vulgaris. The PAHPI also correlates well with the emotional impact of PIH as measured by the Skindex-29. Future studies should assess the ability of the PAHPI to change with improvement of PIH from acne after treatment.