What is the IGA scale and its clinical meaning?

IGA: 0=clear (no lesions); 1=almost clear (very faint remaining marks); 2=mild (faint red plaques, minimal scale); 3=moderate (dull red plaques, moderate scale); 4=severe (bright red plaques, thick scale); IGA 0/1 = treatment success endpoint in clinical trials.

Is IGA equivalent across different skin diseases?

IGA 0-4 scales are used for psoriasis (IGA-mod), atopic dermatitis (IGA-AD), and rosacea (IGA); the scales are calibrated differently for each disease; IGA for psoriasis and AD are NOT interchangeable.

What composite outcome combines PASI and IGA?

PASI 90 + IGA 0/1 is the key co-primary endpoint in most modern biologic trials; achieving both represents near-complete clearance; FDA requires PASI 75 + IGA 0/1 as minimum for approval for most new psoriasis therapies.

How is BSA measured for skin disease treatment eligibility?

Patient palm method: palm of hand + digits = approximately 1% BSA; rule-of-nines estimates; BSA ≥10% + DLQI >10 = biologic eligible for psoriasis; BSA ≥10% + IGA ≥3 = biologic eligible for AD in most European guidelines.

What clinical outcome is IGA 0 (clear) associated with in psoriasis?

IGA 0 (complete clearance) is associated with maximal patient satisfaction, quality of life, and prevention of cumulative psoriatic comorbidity burden; sustained clearance (IGA 0/1) is now the aspirational treatment target.

Investigator Global Assessment (IGA) and BSA Composite Score

Calculates the IGA static global assessment (0-4 scale) and body surface area for psoriasis and atopic dermatitis with treatment eligibility composite scoring for phase III clinical trial interpretation.

⚕ 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 to Use

Enter the values for the scenario you are assessing. Calculates the IGA static global assessment (0-4 scale) and body surface area for psoriasis and atopic dermatitis with treatment eligibility composite scoring for phase III clinical trial interpretation. Use the iga score result to inform your calculation.

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