Sixteen severity ratings and four area scores, weighted by body region, give a total from 0 to 72. EASI-75, a 75% improvement from baseline, is a standard co-primary endpoint in atopic dermatitis trials. Capture every component so the total can be recalculated and checked.
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Area involved
EASITRAErythema
EASITREOedema / papulation
EASITRPExcoriation
EASITRXLichenification
EASITRLAt a glance
In trials
EASI is a calculation on 20 recorded values. If the eCRF stores only the total, nobody can check it, and a single arithmetic slip at a site can change a participant's responder status. Store the four area scores and sixteen sign ratings as separate coded fields, then derive region scores and the total in analysis, where the formula is written once and applied consistently.
Atopic dermatitis trials almost always pair EASI with the validated Investigator Global Assessment for atopic dermatitis (vIGA-AD, 0 to 4) as a co-primary endpoint, and with a peak pruritus NRS diary for itch. The DLQI is a common quality of life secondary.
Area is scored 0 (none), 1 (1 to 9%), 2 (10 to 29%), 3 (30 to 49%), 4 (50 to 69%), 5 (70 to 89%) or 6 (90 to 100%) of the region. A dropdown with the percentage bands as labels removes the need for assessors to remember the cut-offs.
Week 16
7.2 / 72
Calculation
| Region | Weight, age 8 and over | Weight, under 8 |
|---|---|---|
| Head and neck | 0.1 | 0.2 |
| Upper limbs | 0.2 | 0.2 |
| Trunk | 0.3 | 0.3 |
| Lower limbs | 0.4 | 0.3 |
Region score = (erythema + oedema/papulation + excoriation + lichenification) × area score × weight. Total = sum of the four region scores. Severity band cut-offs vary between publications.
In Capture
Each region is a section with an area dropdown and four sign ratings. Range checks stop out-of-scale values, every component exports as its own variable with labels, and source data verification can be switched on for the fields that drive the endpoint.
Changed by Data manager · reason: critical safety value added
Copy the template into the free sandbox and enter a test assessment.
Assessors
EASI depends on the assessor's judgement of redness, thickness and extent, so inter-rater differences are real. Trials use trained assessors, keep the same assessor for a participant where possible, and schedule assessments at a consistent time relative to topical treatment and bathing. Photographs are sometimes taken for training or central review; if you collect them, handle them as identifiable data under your consent and privacy arrangements.
Record the assessor on the form and whether the child weighting applies. For participants who turn 8 during a long study, the protocol should state whether weights change with age or stay fixed from baseline, so the calculation is consistent.
Before go-live
Four area scores and sixteen sign ratings as separate fields.
Adult or child weighting, and the rule at age 8.
Whether 0.5 steps are allowed for signs.
Consistent assessors across visits.
vIGA-AD form alongside EASI.
Peak pruritus NRS if part of the endpoints.
For each of four regions, the sum of four sign ratings (0 to 3) is multiplied by the area score (0 to 6) and a region weight. The four region scores are added for a total of 0 to 72.
An improvement of at least 75% from the baseline EASI total. It is a common co-primary endpoint in atopic dermatitis trials.
Yes. Children under 8 use 0.2, 0.2, 0.3 and 0.3 for head and neck, upper limbs, trunk and lower limbs; older participants use 0.1, 0.2, 0.3 and 0.4.
No. Store every component so the total can be recalculated and checked.
The EASI is widely used in research without a licence fee. Check the current guidance from its developers before use.
Components are stored as coded values, and region scores and the total are derived from them in analysis.
Every component coded and checked. Free sandbox.