The Eczema Area and Severity Index (EASI) is an investigator-assessed scoring system used to quantify the clinical signs and extent of atopic dermatitis (eczema). It’s widely used in clinical practice and especially in clinical trials because it gives a standardized way to track severity over time and response to treatment. PMC+2DermNet®+2

What EASI measures

EASI combines:

• Severity of 4 signs (each scored 0–3) in each body region:
  1. Erythema (redness)
  2. Induration/papulation (thickness/swelling)
  3. Excoriation (scratch marks)
  4. Lichenification (skin thickening) DermNet®+1
• Area involved in each region, converted to an area score (0–6) using standard % bands (0%, 1–9%, 10–29%, 30–49%, 50–69%, 70–89%, 90–100%). DermNet®+1

How it’s calculated (overview)

The body is divided into 4 regions: Head/Neck, Upper Limbs, Trunk, Lower Limbs.
For each region:

Region score = (sum of 4 sign severities) × (area score) × (region weighting)

Weightings depend on age group (commonly ≥8 years vs 0–7 years). The final EASI total is the sum of all region scores, ranging 0–72. DermNet®+1

Interpreting the score (common bands)

A commonly used interpretation is:

• 0 = clear
• 0.1–1.0 = almost clear
• 1.1–7.0 = mild
• 7.1–21.0 = moderate
• 21.1–50.0 = severe
• >50 = very severe PMC