1. What is Body Surface Area (BSA) Psoriasis Calculator?

Definition: This calculator estimates the percentage of body surface area affected by psoriasis using the palm method (1 palm ≈ 1% BSA).

Purpose: It helps dermatologists and patients quantify psoriasis severity and track treatment progress.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \%BSA \) — Percentage of body surface area affected
• \(\text{Sum of affected areas}\) — Total area affected measured in palms (1 palm ≈ 1% of total BSA)

Explanation: Each palm-sized area of psoriasis represents approximately 1% of total body surface area.

3. Importance of BSA Measurement in Psoriasis

Details: BSA assessment helps classify psoriasis severity (mild: <3%, moderate: 3-10%, severe: >10%) and guide treatment decisions.

4. Using the Calculator

Tips: Estimate affected areas by counting how many palm-sized areas are covered by psoriasis lesions. Enter this number in the calculator.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the palm method?
A: The palm method provides a quick estimate. For precise measurement, healthcare providers may use more detailed methods like the Rule of Nines.

Q2: What counts as one palm area?
A: One palm equals the patient's own palm with fingers closed, representing approximately 1% of their total body surface area.

Q3: How does BSA relate to psoriasis severity?
A: Generally, <3% is mild, 3-10% is moderate, and >10% is severe, though other factors like location and symptoms also matter.

Q4: Should I include unaffected skin between lesions?
A: No, only count areas actually covered by psoriasis plaques.

Q5: How often should I measure my BSA affected?
A: Regular monitoring (e.g., monthly) helps track treatment effectiveness, especially when starting new therapies.