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.

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Frequently Asked Questions

What is the IGA scale and its clinical meaning?

Is IGA equivalent across different skin diseases?

What composite outcome combines PASI and IGA?

How is BSA measured for skin disease treatment eligibility?

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