The Definition of Psoriasis Severity and Treatment Target of Psoriasis: Korean Expert Consensus Using the Modified...

The emergence of new treatments has significantly elevated treatment expectations for psoriasis. However, existing Korean severity definitions and treatment targets of psoriasis remain primarily centered on traditional Psoriasis Area and Severity Index (PASI) and Body Surface Area (BSA) thresholds, often underestimating the disease burden in high-impact special areas.

To develop a revised Korean expert consensus on psoriasis severity and treatment targets that incorporate the clinical significance of special areas and reflect the evolving therapeutic landscape.

A modified Delphi method was employed involving a panel of 65 dermatologists specializing in psoriasis from universities and training hospitals across South Korea. Two rounds of anonymous web-based surveys were conducted.

A strong consensus was achieved on a new definition of moderate-to-severe psoriasis: (1) PASI ≥10, or (2) 5< PASI <10 with concomitant special area involvement (defined as ≥30% affected surface area of the specific site and a static Physician's Global Assessment (sPGA) score ≥3). For treatment targets, the panel established 'Absolute PASI ≤2' as the primary realistic goal. Site-specific goals were defined for special areas, to achieve an affected surface area <10% or an sPGA of 0/1. The Dermatology Life Quality Index was excluded from the mandatory severity definition or treatment target to preserve objectivity and feasibility in high-volume clinical settings.

This consensus provides a practical and objective framework for managing psoriasis in Korea. These recommendations provide quantifiable criteria and stringent targets to optimize clinical decisions and patient outcomes in the era of advanced therapeutics.