SALT Score

Severity of Alopecia Tool — Olsen et al. (National Alopecia Areata Foundation), 2004 · SALT II: Olsen & Canfield, 2016

Purpose
Quantifies the percentage of scalp surface with terminal hair loss in alopecia areata; the standard endpoint in clinical trials.
Population
Adults and children with alopecia areata (patchy, totalis or universalis). Scalp only — body hair and nails are rated separately (B and N categories).
Formula
SALT = Σ (% hair loss in region × region weight) · Left 18% · Right 18% · Top 40% · Back 24% · Range 0–100
Severity bands
Olsen 2004: S0 = 0 · S1 < 25 · S2 25–49 · S3 50–74 · S4 75–99 (S4a 75–95, S4b 96–99) · S5 = 100. Trial endpoints: SALT ≤ 20, SALT ≤ 10, SALT50/75/90.
🗺️ Scalp hair loss by region

Estimate the percentage of each scalp region without terminal hair (0–100 %). Views: left side, right side, top (vertex) and back (occiput). SALT II refines the estimate by dividing each region into 1 % segments — enter the resulting percentage here.

Improvement = (baseline − current) / baseline × 100. SALT50/75/90 = ≥ 50/75/90 % improvement from baseline.
📋 Olsen 2004 scalp hair-loss categories

The S category describes the extent of scalp hair loss at a given visit. S4 is subdivided because S4b (96–99 %) has a poorer prognosis for regrowth than S4a. Body hair (B0–B2) and nails (N0–N2) are rated separately in the same guidelines.

📚 References
  1. Olsen EA, Hordinsky MK, Price VH, et al. Alopecia areata investigational assessment guidelines — Part II. National Alopecia Areata Foundation. J Am Acad Dermatol. 2004;51(3):440–7. doi:10.1016/j.jaad.2003.09.032
  2. Olsen EA, Canfield D. SALT II: a new take on the Severity of Alopecia Tool (SALT) for determining percentage scalp hair loss. J Am Acad Dermatol. 2016;75(6):1268–70. doi:10.1016/j.jaad.2016.08.042
  3. Wyrwich KW, Kitchen H, Knight S, et al. The Alopecia Areata Investigator Global Assessment scale: a measure for evaluating clinically meaningful success in clinical trials. Br J Dermatol. 2020;183(4):702–9. doi:10.1111/bjd.18883
  4. King B, Ohyama M, Kwon O, et al. Two phase 3 trials of baricitinib for alopecia areata (BRAVE-AA1, BRAVE-AA2). N Engl J Med. 2022;386(18):1687–99. doi:10.1056/NEJMoa2110343
  5. King B, Zhang X, Harcha WG, et al. Efficacy and safety of ritlecitinib in adults and adolescents with alopecia areata (ALLEGRO phase 2b/3). Lancet. 2023;401(10387):1518–29. doi:10.1016/S0140-6736(23)00222-2
Clinical decision support only. This tool is intended to assist clinical assessment and does not replace professional judgment. Always interpret results in the context of the individual patient.