Constitutive Skin Color and Melanin Baseline
Baseline pigmentation sets the starting point for phototype assessment.
- 6: Phototypes (Fitzpatrick I–VI scale)
- Eumelanin: Pigment type (dominant in darker skin)
- 1975: Scale origin (Fitzpatrick, Harvard)
- Self-report: Assessment (history-based questionnaire)
Baseline pigmentation
Placeholder: melanin quantity and type set constitutive skin color.
UV Exposure Burn and Tan Reaction Test
A test UV dose is applied and the erythema/pigment response observed.
- MED test: Test method (minimal erythema dose)
- 24h: Read time (post-exposure check)
- Burn: Outcome A (erythema, no pigment gain)
- Tan: Outcome B (delayed pigment darkening)
Burn vs tan response
Placeholder: UV test dose separates burn-prone from tan-prone skin.
Burn-Prone Classification — Type I to III
Fair phototypes show high sensitivity and limited natural protection.
- Always burns: Type I (never tans)
- Usually burns: Type II (tans minimally)
- Sometimes burns: Type III (tans gradually)
- Elevated: Skin cancer risk (for types I–II)
Fair skin sensitivity
Placeholder: low melanin means faster erythema onset at lower UV dose.
Tan-Prone Classification — Type IV to VI
Darker phototypes tolerate more UV before erythema appears.
- Rarely burns: Type IV (tans well)
- Very rarely burns: Type V (tans darkly)
- Never burns: Type VI (deeply pigmented)
- Higher: MED value (more UV tolerated)
High melanin protection
Placeholder: greater eumelanin content raises the UV tolerance threshold.
Phototype-Based Treatment Dose Selection
Starting UVB dose for phototherapy is set from phototype and history.
- 130 mJ/cm²: Type I start (lowest starting dose)
- 400 mJ/cm²: Type VI start (highest starting dose)
- ~10-20%: Increment rule (per session if tolerated)
- Minimal erythema: Goal (without overt burn)
Safe starting dose
Placeholder: dose is scaled to phototype to balance efficacy and safety.
Placeholder: phototype guides safe, effective narrowband UVB dosing.