How Severity Is Graded in Alopecia Areata

Understanding how severe your hair loss is can help guide treatment choices, track progress and set realistic expectations. The most widely accepted method to quantify alopecia areata (AA) severity is the Severity of Alopecia Tool (SALT) score. Below, we explain how the SALT score works, what the key severity categories are, and how other factors—like eyelashes, eyebrows or nails—may influence overall assessment.

What Is the SALT Score?

Developed by Olsen & Hordinsky (2004), the SALT score provides an objective, reproducible “alopecia severity score” expressed from 0% (no hair loss) to 100% (complete scalp hair loss). It divides the scalp into four regions, estimates percent hair loss in each, then applies fixed weightings to generate a single number.

1. Scalp Regions & Weightings

   • Vertex (top): 40% of total scalp area
   • Right profile/parietal: 18%
   • Left profile/parietal: 18%
   • Occipital (back): 24%

2. Estimating Regional Hair Loss
   For each region, estimate what percentage of hair is missing. For example, if half the hair is gone on the right parietal, that’s 50% loss in a region that counts for 18% of the scalp.

3. Calculating the Total SALT Score
   Total SALT = (Region % loss × Region weight) summed across all four regions.
   Example:

   • Vertex: 30% loss × 0.40 = 12
   • Right parietal: 50% loss × 0.18 = 9
   • Left parietal: 0% loss × 0.18 = 0
   • Occipital: 20% loss × 0.24 = 4.8
     ––> Total SALT = 12 + 9 + 0 + 4.8 = 25.8

4. Interpreting the SALT Score
   Clinically, these percentages map to severity grades:

   • S0: 0% hair loss (normal)
   • S1: 1–24% (mild)
   • S2: 25–49% (moderate)
   • S3: 50–74% (severe)
   • S4: 75–99% (very severe)
   • S5: 100% (alopecia totalis or universalis if eyebrows/eyelashes are also lost)

Why SALT Matters

• Standardization: Provides a consistent, numerical measure for clinical trials and practice.
• Tracking: Allows you and your doctor to objectively see if treatments are working.
• Communication: Offers a common language for dermatologists and researchers worldwide.

Clinical Subtypes & Severity

Alopecia areata can present in different patterns beyond patchy scalp hair loss. Severity grading often considers these subtypes:

• Patchy AA
– Discrete round or oval bald patches. Severity based on SALT.
• Alopecia Totalis (AT)
– Complete scalp hair loss (S5).
• Alopecia Universalis (AU)
– Total loss of scalp hair, eyebrows and eyelashes (S5 plus eyebrow/eyelash involvement).

Beyond the Scalp: Eyebrows, Eyelashes & Nails

While SALT focuses on scalp hair, many people with AA also lose eyebrow/eyelash hair or develop nail changes. Though not part of the SALT formula, these features can affect overall disease burden:

• Eyebrow/Eyelash Involvement
– Graded by percent hair loss or complete absence.
– Important for psychosocial impact and guiding therapies (e.g., topical vs. systemic).

• Nail Changes
– Pitting, ridging or brittleness occur in up to 50% of AA patients.
– Assessed qualitatively: mild, moderate or severe nail dystrophy.

Other Severity Tools

Although SALT is the gold standard, research studies and clinics may also use:
• Alopecia Areata Symptom Impact Scale (AASIS) – measures patient‐reported symptoms.
• Alopecia Density and Regrowth Scale (ADRS) – visually tracks hair regrowth density.
• Alopecia Areata Investigational Assessment Guidelines – a composite of SALT plus photographs and patient feedback.

Putting It All Together: Example Case

Jane, a 28-year-old with three round bald patches, has hair loss estimated as:
• Vertex: 10% loss → 10% × 40% = 4
• Right parietal: 30% loss → 30% × 18% = 5.4
• Left parietal: 20% loss → 20% × 18% = 3.6
• Occipital: 0% loss → 0% × 24% = 0
Total SALT = 4 + 5.4 + 3.6 + 0 = 13
Grade = S1 (mild, 1–24% hair loss).

Jane also has partial eyebrow thinning (≈50%) and mild nail pitting. Her dermatologist classifies her overall alopecia severity as mild to moderate and discusses topical steroids and phototherapy as initial options.

Why Knowing Your Severity Helps You

• Treatment Decisions: Mild cases (S1–S2) often start with topical or injectable steroids. More severe cases (S3–S5) may require systemic therapies.
• Monitoring Progress: An objective score makes it easy to tell if hair is regrowing or if loss is stabilizing.
• Emotional Support: Understanding where you land on the scale demystifies the condition and helps set realistic goals.

Next Steps & When to Seek Help

If you’re noticing patchy hair loss, eyebrow thinning or nail changes, you don’t have to wait for a full-blown bald spot before seeking guidance. You may want to try a free, online symptom check for Alopecia Areata and see how your symptoms align with common patterns.

Regardless of your score, always speak to a doctor about anything that feels sudden, severe or impacts your quality of life. Hair loss can be stressful, but early assessment and management can improve outcomes and help you regain confidence.

Key Takeaways

• The SALT score is the standard “alopecia severity score” in AA, ranging from 0% to 100%.
• Severity grades (S0–S5) guide treatment choices from topical agents to systemic medications.
• Involvement of eyebrows, eyelashes and nails adds to overall disease impact, even if not in the scalp score.
• Regular assessment helps track progress and adjust therapies promptly.
• Consider an online symptom check for Alopecia Areata to better understand your signs and prepare for a doctor’s visit.

Always remember: an accurate severity assessment is the first step toward effective management. If you have concerns about life-threatening or serious symptoms—such as rapid, widespread hair loss or associated systemic signs—contact your healthcare provider promptly.