EASI Calculator (Eczema Area and Severity Index)

Four regions, four signs each, and region multipliers that DEPEND ON AGE: head and neck 0.1 at eight and over but 0.2 under eight, lower limbs 0.4 and 0.3. The same findings give different totals.

Last updated 8 Oct 2026

Eczema Area and Severity Index

4 regions, age-dependent weights, 0–72

Age groupThis field changes the region multipliers, not just a little. Under 8 years the head and neck multiplier doubles to 0.2 and the lower limb multiplier falls to 0.3, because a young child’s head is a far larger share of the surface and the legs a smaller one. The trunk (0.3) and the upper limbs (0.2) are unchanged at every age, and both sets sum to 1.0, so the maximum is 72 either way.

Head and neck — erythemaErythema — the redness. Grade the average of the involved skin in this region. On deeply pigmented skin erythema may read as violaceous or simply darker, and under-grading it here is a recognised source of systematic under-scoring.

Head and neck — oedema or papulationOedema and papulation — swelling and the raised, bumpy quality of acute eczema. This is the sign that separates an acute flare from a chronic plaque.

Head and neck — excoriationExcoriation — scratch marks and broken skin. It is a sign of itch, which is the symptom the index has no other term for.

Head and neck — lichenificationLichenification — the thickened, leathery, accentuated skin markings of long-standing rubbing. It is the slowest sign to respond and the one that lags behind a drug’s effect.

Head and neck — area involved (0.1 at 8 and over, 0.2 under 8)Per cent of the head and neck with active eczema, not per cent of the whole body.

Upper limbs — erythema

Upper limbs — oedema or papulation

Upper limbs — excoriation

Upper limbs — lichenification

Upper limbs — area involved (0.2 at every age)Per cent of the upper limbs with active eczema, not per cent of the whole body.

Trunk — erythema

Trunk — oedema or papulation

Trunk — excoriation

Trunk — lichenification

Trunk — area involved (0.3 at every age)Per cent of the trunk with active eczema, not per cent of the whole body.

Lower limbs — erythema

Lower limbs — oedema or papulation

Lower limbs — excoriation

Lower limbs — lichenification

Lower limbs — area involved (0.4 at 8 and over, 0.3 under 8)Per cent of the lower limbs with active eczema, not per cent of the whole body.

15.2pointsExample

8 years and over. Head and neck E2 O1 X1 L0, area 10–29% (2); upper limbs E2 O2 X2 L1, area 30–49% (3); trunk E1 O1 X1 L0, area 10–29% (2); lower limbs E2 O2 X2 L1, area 30–49% (3)

Formula

EASI = Σ_regions (E + O + X + L) × A × multiplier
E, O, X, L = erythema, oedema/papulation, excoriation, lichenification, each 0–3 · A = area category 0–6
8 years and over: head/neck 0.1 · upper limbs 0.2 · trunk 0.3 · lower limbs 0.4
Under 8 years: head/neck 0.2 · upper limbs 0.2 · trunk 0.3 · lower limbs 0.3
Total 0–72

the age-dependent multipliers: only TWO of the four change, and they change in opposite directions: the head and neck multiplier doubles from 0.1 to 0.2 under eight years, and the lower limb multiplier falls from 0.4 to 0.3. The trunk stays at 0.3 and the upper limbs at 0.2. Both sets sum to 1.0, so the maximum is 72 either way, and a patient with no head or lower-limb involvement scores identically on both sets — which is the diagnostic fact about where the difference lives
the boundary is 8 years: stated as “8 years and over” against “under 8” in the TRuE-AD3 analysis plan, and as “0 to 7 years” on DermNet. The two phrasings describe the same cut
four signs, not three: erythema, oedema or papulation, excoriation and lichenification, each 0 to 3. PASI’s three signs are erythema, induration and desquamation on 0 to 4, so the two indices are not comparable even though both run 0 to 72
half steps: DermNet records that half scores are allowed on the severity signs, so the sign fields here take 0.5 steps. Most trials score whole numbers; both are representable
the severity strata: 0 clear; 0.1 to 1.0 almost clear; 1.1 to 7.0 mild; 7.1 to 21.0 moderate; 21.1 to 50.0 severe; 50.1 to 72.0 very severe. Reproduced verbatim from the TRuE-AD3 statistical analysis plan, which prints them without a citation; they descend from Leshem and colleagues’ interpretability study. Band edges here are INCLUSIVE, because the published ranges are
what it does not contain: no itch, no sleep loss, no flare frequency, no treatment burden, no site weighting beyond the four regions. The SCORAD does include two patient-reported items and is a different instrument for that reason

Worked example

8 years and over. Head and neck E2 O1 X1 L0, area 10–29% (2); upper limbs E2 O2 X2 L1, area 30–49% (3); trunk E1 O1 X1 L0, area 10–29% (2); lower limbs E2 O2 X2 L1, area 30–49% (3)
Head and neck: (2 + 1 + 1 + 0) × 2 × 0.1 = 0.8
Upper limbs: (2 + 2 + 2 + 1) × 3 × 0.2 = 4.2
Trunk: (1 + 1 + 1 + 0) × 2 × 0.3 = 1.8
Lower limbs: (2 + 2 + 2 + 1) × 3 × 0.4 = 8.4
0.8 + 4.2 + 1.8 + 8.4 = 15.2 points, moderate on the published banding
Now change nothing except the age group. Under 8 years the head and neck term becomes 4 × 2 × 0.2 = 1.6 and the lower-limb term becomes 7 × 3 × 0.3 = 6.3, so the total becomes 13.9 — the same child, the same findings, 1.3 points lower, because the legs lose more than the head gains
Strip out the head and the legs entirely and the two age sets agree exactly, at 4.2 + 1.8 = 6.0. The whole age difference lives in those two regions

The two published multiplier sets

Read in three independent sources that agree: the PPOP EASI ASTAR scoring form, DermNet’s EASI page and the TRuE-AD3 statistical analysis plan, which prints both sets as text. The ASTAR table came through partly garbled, which is why two further sources were read before these numbers were used.
Region	8 years and over	Under 8 years	Maximum contribution, 8 and over
Head and neck	0.1	0.2	7.2 points
Upper limbs	0.2	0.2	14.4 points
Trunk	0.3	0.3	21.6 points
Lower limbs	0.4	0.3	28.8 points
Sum of multipliers	1.0	1.0	72 points

EASI against PASI — the same range, different instruments

Both run 0 to 72 and neither number means anything on the other scale. The arithmetic coincidence — four signs at 3 against three signs at 4, both times six area categories and multipliers summing to one body — is the only thing they share.
	EASI	PASI
Disease	Atopic dermatitis	Psoriasis
Signs	Erythema, oedema/papulation, excoriation, lichenification	Erythema, induration, desquamation
Sign scale	0 to 3 (half steps allowed)	0 to 4
Regions	Head/neck, upper limbs, trunk, lower limbs	The same four
Multipliers	Age-dependent: 0.1/0.2/0.3/0.4 at 8 and over, 0.2/0.2/0.3/0.3 under 8	0.1/0.2/0.3/0.4 at every age
Range	0 to 72	0 to 72

The age-dependent weights are the thing to get right

EASI was published in 2001 by Hanifin and the EASI Evaluator Group as a reliability-tested instrument for atopic dermatitis, built on the same four-region frame as PASI but with four signs instead of three and a 0 to 3 scale instead of 0 to 4. It is now the signs instrument the Harmonising Outcome Measures for Eczema initiative recommends for trials, and the usual primary endpoint is EASI-75 — a 75 per cent relative improvement from baseline, the direct analogue of PASI 75.

The detail that separates a correct implementation from a plausible one is that the region multipliers depend on age. For a patient of eight years or over they are 0.1 for the head and neck, 0.2 for the upper limbs, 0.3 for the trunk and 0.4 for the lower limbs. Under eight years the head and neck multiplier doubles to 0.2 and the lower limb multiplier falls to 0.3, because a young child’s head is a much larger share of the body surface and the legs a smaller one. Only those two change; both sets still sum to 1.0, so the maximum is 72 at any age. The practical consequence is that a child with head and leg eczema scores differently from an adult with identical findings, and a calculator that silently applies the adult set to a four-year-old is wrong by whatever those two regions contribute. This page makes the age group the first input for that reason.

Two further things about the signs. Excoriation is the only proxy the index has for itch and it is a poor one: a patient who does not scratch loses that component without the disease changing. Lichenification is the slowest sign to resolve, so an EASI measured early in a response is dominated by a component the drug has not had time to touch. Neither itch nor sleep loss appears in the total at all — the SCORAD includes both as patient-reported items and is a different instrument for it.

The atopy laboratory sits alongside this page rather than inside it: the absolute eosinophil count calculator, the total IgE unit converter and the specific IgE class interpreter describe the atopic state and do not grade the skin. No proprietor, licence portal or permission notice was found for this instrument; it is a journal-published scoring scheme, restated here with attribution rather than reproduced from a licensed questionnaire. No patient-reported outcome measure is computed anywhere on this site. The Dermatology Life Quality Index is owned and licensed by Cardiff University, whose own page states that its measures may not be reproduced in any publication and charges per patient for non-clinical use, so it is named here and never scored.

Frequently asked questions

What are the EASI region multipliers?

For patients aged 8 years and over: head and neck 0.1, upper limbs 0.2, trunk 0.3, lower limbs 0.4. For patients under 8: head and neck 0.2, upper limbs 0.2, trunk 0.3, lower limbs 0.3. Only the head and the lower limbs change with age, and both sets sum to 1.0.

Does the EASI maximum change with age?

No. Both multiplier sets sum to 1.0, so the maximum is 72 either way: four signs at 3 points is 12, times an area category of 6 is 72. What changes is how a given pattern of involvement is distributed across that range.

What EASI score is mild, moderate or severe?

The published strata are 0 clear, 0.1 to 1.0 almost clear, 1.1 to 7.0 mild, 7.1 to 21.0 moderate, 21.1 to 50.0 severe and 50.1 to 72.0 very severe. They are reproduced verbatim in the TRuE-AD3 statistical analysis plan and descend from Leshem and colleagues’ interpretability study.

Is EASI the same as PASI with different weights?

No. EASI scores four signs — erythema, oedema or papulation, excoriation, lichenification — on a 0 to 3 scale; PASI scores three on 0 to 4. The multipliers are age-dependent in EASI and fixed in PASI. Both happen to run 0 to 72, and an EASI of 20 is not comparable to a PASI of 20.

Are half scores allowed on the EASI severity signs?

DermNet records that they are, and this page accepts them in 0.5 steps. Most clinical trials score the signs in whole numbers, so a half-step total will not match a trial protocol’s expected granularity even though it is faithful to the original description.

Related calculators

References

Hanifin JM, Thurston M, Omoto M, Cherill R, Tofte SJ, Graeber M; EASI Evaluator Group. The eczema area and severity index (EASI): assessment of reliability in atopic dermatitis. Exp Dermatol. 2001;10(1):11–18. PMID 11168575. The derivation publication.
DermNet. EASI score — both multiplier sets, including head and neck ×0.2 and lower limbs ×0.3 for children aged 0–7. dermnetnz.org/topics/easi-score
Incyte Corporation. TRuE-AD3 statistical analysis plan, NCT04921969 — both EASI multiplier sets and the six severity strata (0 clear; 0.1–1.0 almost clear; 1.1–7.0 mild; 7.1–21.0 moderate; 21.1–50.0 severe; 50.1–72.0 very severe).
Pediatric Dermatology Research Alliance. EASI ASTAR v2.0, 9 October 2018 — EASI scoring form with the age-dependent region multipliers. ppopderm.org
Leshem YA, Hajar T, Hanifin JM, Simpson EL. What the Eczema Area and Severity Index score tells us about the severity of atopic dermatitis: an interpretability study. Br J Dermatol. 2015;172(5):1353–7. The interpretability study the six EASI severity strata descend from.
Regenstrief Institute. LOINC 62902-2 — PhenX eczema protocol (Eczema Area and Severity Index), carrying no third-party copyright or permission statement. loinc.org/62902-2
Almirall. Índices de gravedad en dermatitis atópica, version 4, December 2025 — SCORAD = A/5 + 7B/2 + C with the severity cut-offs under 25, 25–50 and above 50, and the EASI adult multipliers. dermatologia.almirallmed.es
Cardiff University. Quality of life questionnaires — the DLQI’s ownership, the prohibition on reproducing the measures, and the per-patient fee schedule for non-clinical use. cardiff.ac.uk/medicine/resources/quality-of-life-questionnaires

Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/