What PASI score is considered severe psoriasis requiring biologic therapy?

PASI >10 with BSA >10% and DLQI >10 defines severe psoriasis typically qualifying for biologic treatment; PASI >10 alone or DLQI >10 with significant impact may qualify; psoriatic arthritis component also indicates treatment need.

What is the PASI 75/90/100 significance?

PASI 75 (75% reduction from baseline): historical threshold for treatment success; PASI 90: modern treatment target with most biologics; PASI 100 (completely clear skin): achievable with IL-23 inhibitors (risankizumab, guselkumab) in 30-50% of patients.

How is PASI calculated for each body region?

For each region: erythema (0-4) + induration (0-4) + desquamation (0-4) = severity sum (0-12); then multiply by area score (0-6) and regional weighting factor (head 0.1, upper 0.2, trunk 0.3, lower 0.4); sum all regions = PASI 0-72.

What biologic mechanisms treat psoriasis?

TNF-α inhibitors (adalimumab, etanercept, infliximab): PASI 75 50-80%; IL-17A inhibitors (secukinumab, ixekizumab): PASI 90 60-75%; IL-23 inhibitors (risankizumab, guselkumab): PASI 90 75-85%; IL-12/23 inhibitor (ustekinumab): PASI 75 70%.

What special sites lower PASI threshold for treatment?

Palmoplantar psoriasis, nail psoriasis, genital psoriasis, scalp psoriasis, and facial psoriasis are "difficult sites" that qualify for systemic/biologic treatment at lower PASI scores due to significant functional impairment and QoL impact.

Psoriasis Area and Severity Index (PASI) Score Calculator

Calculates PASI score for psoriasis severity across four body regions (head, trunk, upper extremities, lower extremities) using erythema, induration, desquamation, and area scores, with PASI 75/90/100 response thresholds for biologic therapy.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.

How It Works

Each component has a specific meaning:

Four body regions (head — The four body regions (head recorded for the scenario being assessed.
Trunk — The trunk recorded for the scenario being assessed.
Upper extremities — The upper extremities recorded for the scenario being assessed.
Lower extremities) — The lower extremities) recorded for the scenario being assessed.

Note: Interpret the pasi score result against the thresholds and context described above.

How to Use

Enter the four body regions (head, trunk, upper extremities, lower extremities) for the scenario you are assessing. Calculates PASI score for psoriasis severity across four body regions (head, trunk, upper extremities, lower extremities) using erythema, induration, desquamation, and area scores, with PASI 75/90/100 response thresholds for biologic therapy. Use the pasi score result to inform your calculation.

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