How extensive is the vitiligo today?
Estimate involvement per body region in hand units (one hand unit — your palm plus fingers — is about 1% of body surface), grade the residual depigmentation within the lesions on the published anchor scale, and the tool computes the Vitiligo Area Scoring Index (0–100) plus the facial F-VASI (0–3). Save a score per visit to track VASI 50 / 75 / 90 repigmentation response. Everything stays on this device.
VASI has no validated absolute-severity bands — the score is a raw value and scale position. Use change across visits (VASI50/75/90) to judge response.
Each save records both the T-VASI and the F-VASI for that date, so your history can compute VASI 50 / 75 / 90 reductions from baseline — the yardstick that actually measures repigmentation. This is an educational self-assessment, not a diagnosis: use a consistent hand-size reference across visits and discuss scores and treatment response with your dermatologist.
Source: Hamzavi I, Jain H, McLean D, Shapiro J, Zeng H, Lui H. Parametric modeling of narrowband UV-B phototherapy for vitiligo using a novel quantitative tool: the Vitiligo Area Scoring Index. Arch Dermatol. 2004;140(6):677–683. Depigmentation anchors and 6-region method as applied in subsequent vitiligo trials.
Saved only on this device — and browsers erase site data. A history clear, a private window, or Safari's automatic deletion after seven days without a visit will take this log with it. The fix is a free DermApproved account: it backs this up automatically and puts it on every device you sign in to — details in how storage works.
How the VASI calculator works
The Vitiligo Area Scoring Index (Hamzavi et al., Archives of Dermatology, 2004) is the standard quantitative measure of vitiligo used in clinics and trials. For each of six body regions — head/neck, hands, upper extremities, trunk, lower extremities, and feet — you estimate the involved area in hand units (one hand unit, your palm plus fingers, covers about 1% of body surface) and grade the residual depigmentation within those lesions on the published anchor scale: 100% (no pigment present), 90% (specks of pigment remain), 75% (depigmented area exceeds pigmented), 50% (equal), 25% (pigmented exceeds depigmented), or 10% (specks of depigmentation only). Each region contributes hand units × depigmentation fraction, and the sum is the T-VASI (0–100). The facial F-VASI applies the same product to the face only — about 3% of body surface, so it runs 0–3 and is reported separately, never added to the total. An optional genitals region (≈1% BSA) is included as a non-standard add-on: track it consistently or not at all, since it changes comparability with published T-VASI values.
Reading the number is different from most severity scores: VASI has no validated mild/moderate/severe bands. Its value is change over time — VASI 50, 75, and 90 mark a 50%, 75%, or 90% reduction from your baseline score, and F-VASI75 is the usual primary endpoint in facial vitiligo trials. Save a score at each assessment and the history below the tool computes those reductions automatically. If you just want a quick read on overall extent, the BSA calculator's vitiligo mode estimates how much skin is involved; VASI is the finer, trial-grade instrument because it also captures partial repigmentation within patches — pigment returning before area shrinks. Pair either with the photo tracker: dated photos plus a dated score is exactly the evidence a dermatologist wants when judging whether treatment is working.
Common questions
What exactly is a "hand unit"?
Your own palm plus fingers — the whole palmar surface — covers roughly 1% of your own body surface area, which makes it a built-in measuring device. To score a region, estimate how many of your hands it would take to cover the depigmented patches there, in half-hand steps. Because it scales with your own body, the same rule works at any age or size.
How is VASI different from a plain BSA percentage?
BSA counts extent only — how much skin is involved. VASI multiplies each region’s extent by how depigmented those patches actually are, on a 0–100% anchor scale, so a patch that is regaining pigment lowers the score even before it shrinks. That is why trials use VASI to measure repigmentation: it captures partial improvement that a pure area measure misses.
Why does the face get its own F-VASI score?
Facial vitiligo carries the most visible impact and responds differently to treatment, so trials score it separately. The F-VASI area — forehead and cheeks to the jawline, including nose and eyelids — is about 3% of body surface, so F-VASI runs 0–3 and is never added into the total-body score. F-VASI75, a 75% reduction from baseline, is the usual primary endpoint in facial vitiligo trials.
What counts as a meaningful improvement in my score?
VASI has no validated absolute-severity bands — a single number is just a starting point. Response is judged as percentage reduction from your baseline score: VASI 50, 75 and 90 mark a drop of at least 50%, 75% and 90%. Save a score here at each assessment and the history computes those reductions against your first entry automatically.
Is my score history private?
Entirely — every score you save lives in your own browser’s local storage on this device, and nothing is uploaded to DermApproved or anywhere else. The trade-off is that clearing browser data erases the history, so if you’re tracking treatment response over months, download a backup from My Library now and then.