Vitiligo Area Scoring Index (VASI)

DESCRIPTION:
Developed and validated in 2004, the VASI is a quantitative, clinician-reported outcome tool that provides a global assessment of vitiligo. Similar to the Psoriasis Area and Severity Index (PASI), the VASI provides a single score that represents both disease severity, level of depigmentation, and extent of spread. With VASI, clinicians can measure disease severity and change in disease activity over time.^1-3

DISEASE STATES: 
Vitiligo

VALIDATED USES: 
Screening, Treatment Monitoring

ADMINISTRATION METHOD:
Clinician-Reported Outcome

COMMONLY USED IN:
Clinical Trials

DETAILED DESCRIPTION:
The VASI is one of the most used clinician-reported outcome tools for global assessment of vitiligo.^1-4 Typically, the composite VASI score is based on lesion location on the body, excluding the face, and often is referred to as a total body VASI, or T-VASI. Its total composite score ranges from 0 to 100.^1,2 Facial VASI, or F-VASI, is scored differently and has a maximum score of 3. This is because VASI is based on the “Rule of Nines” and the assumption that the face represents approximately 3% to 3.5% of the total body surface area (BSA).^3,5,6

CALCULATING A T-VASI
The first step, when calculating a T-VASI, is to divide the body into 5 regions: hands, upper limbs, trunk, lower limbs, and feet. The next step is to estimate the affected BSA across each region. This is done with a unique measurement called a “hand unit.” A hand unit (HU) consists of the subject’s palm plus volar surface of all 5 digits—which equates to approximately 1% of BSA. To calculate the T-VASI score, multiply the estimated BSA, based on HUs, by the degree of depigmentation in that body region (e.g., 0, 10%, 25%, 50%, 75%, 90%, 100%) and then sum all body regions.^1-5

T-VASI is calculated as follows:^1-4
T-VASI = ∑ All Body Regions (Hand Units) × (Residual Depigmentation)

T-VASI EXAMPLE⁵

Note: VASI also applies to Segmental Vitiligo.

CALCULATING AN F-VASI
Similar to the T-VASI, an F-VASI is calculated by estimating the affected surface area of the face, which includes the forehead to the original anterior hairline, temples, around the eyes (including eyelids), nose, cheeks (mid and lateral), and around the mouth (including the cutaneous lips and chin). The “face” excludes the vermillion lips, ears, and scalp. However, vitiligo patients often have scattered depigmented patches much smaller than the size of 1 finger and the impact of small facial lesions is not trivial. Therefore, a different unit of measurement called a “fingertip unit” (FTU) is used. The FTU represents the length of the subject’s index finger from distal tip to distal interphalangeal joint (=0.03% BSA). Clinical trials may also use the finger unit or thumb unit consisting of the subject’s pointer finger or thumb from distal tip to metacarpophalangeal joint (=0.1% BSA).^3,6

F-VASI is calculated as follows:^3,6
F-VASI = ∑ Face (Fingertip Units) x (Residual Depigmentation)

F-VASI EXAMPLE^3,6

VALIDITY:
The VASI is correlated with both patient and physician global assessments (P=0.05; P<0.001, respectively).¹ The T-VASI demonstrates high intrarater reliability, strong test-retest reliability, and good responsiveness to detect change.⁷ Both the T-VASI and F-VASI demonstrate strong test-retest reliability (ICC: 0.98; 0.99, respectively) and both demonstrate high interrater reliability.^1,4,7,8 The F-VASI has demonstrated very high sensitivity, able to detect the smallest change (2.2 FTU).^6,8

Both T-VASI and F-VASI have construct validity, reliability, and can differentiate between clinically distinct groups with non-segmental vitiligo.^1,4,6-8

LIMITATIONS:
Both the T-VASI and F-VASI rely on a clinician’s subjective visual estimation.¹ Both may be less sensitive to subtle changes, especially in subjects with fairer skin (Fitzpatrick skin types I–III).^7-9

ICC, Intraclass Correlation Coefficient.

This resource is intended for educational purposes only and is intended for US healthcare professionals. Healthcare professionals should use independent medical judgment. All decisions regarding patient care must be handled by a healthcare professional and be made based on the unique needs of each patient.

References: 1. Hamzavi I et al. Arch Dermatol. 2004;140(6):677-683. 2. Kawakami T et al. Dermatol Res Pract. 2011;2011:750342. 3. Kitchen H et al. Dermatol Ther (Heidelb). 2022;12(7):1623-1637. 4. Pourang A et al. JAAD Int. 2023;16:206-213. 5. Seneschal J et al. J Invest Dermatol. 2016;136(5):902-904. 6. Bae JM et al. J Am Acad Dermatol. 2022;86(2):387-393. 7. Komen L et al. Br J Dermatol. 2015;172(2):437-443. 8. Ezzedine K et al. JAMA Dermatol. 2025;161(1):39-46. 9. Bibeau K et al. Dermatol Ther (Heidelb). 2024;14(8):2223-2234.