• •To assessment psoriasis severity in clinical research or practice.
• •Specifically designed to precisely reflect status of limited disease (< 10% involvement).
• •Recommended by major guidelines (AAD, European Consensus) for documenting treatment success.

• •PASI 75 (75% improvement) is widely accepted as clinically meaningful improvement in trials.
• •Drawback: Lack of sensitivity in mild disease when using categorical area scoring (1-6).
• •Accuracy improves significantly with clinician experience.

Total mPASI = Σ (Region Weight × Lesion Severity × Area Score)

Erythema (E) + Induration (T) + Desquamation (S). None=0, Slight=1, Moderate=2, Severe=3, Very Severe=4.

Unlike standard PASI which uses categorical scores (1 for 1-9%, etc.), mPASI uses the actual percentage involved (Actual% / 10) for values under 10%. 1% = 0.1, 5% = 0.5, 9% = 0.9. This prevents the floor effect of score 1.

• •0: No disease
• •72: Maximal disease severity
• •PASI 75: Indicative of treatment success (75% baseline reduction).