Phototherapy Guidelines Based on Fitzpatrick Skin Type

Introduction to Phototherapy

The American Academy of Dermatology recommends that the Fitzpatrick Skin Type Classification directly determines starting doses and dose escalation protocols for phototherapy, with Type I skin requiring the lowest initial doses and Type VI requiring the highest 1, 2, 3

The American Academy of Dermatology suggests the following starting doses and incremental increases for PUVA phototherapy based on skin type: Type I starts at 0.5 J/cm², Type II at 1.0 J/cm², Type III at 1.5 J/cm², Type IV at 2.0 J/cm², Type V at 2.5 J/cm², and Type VI at 3.0 J/cm², with specific incremental increases for each type 1
For NB-UVB phototherapy, the starting doses are as follows: Type I at 130 mJ/cm², Type II at 220 mJ/cm², Type III at 260 mJ/cm², Type IV at 330 mJ/cm², Type V at 350 mJ/cm², and Type VI at 400 mJ/cm², with specific incremental increases for each type 4

Patients with darker skin types (III-VI) experience significant delayed tanning responses and specific pigmentary complications that require monitoring, including nail changes and mottled hypo- and hyperpigmentation 5, 6
The American Academy of Dermatology recommends that male patients use genital shields during all PUVA treatments due to elevated risk of squamous cell carcinoma of the genitalia, and that all patients wear UV-protective goggles during treatments 5, 6

The American Academy of Dermatology recommends daily broad-spectrum sunscreen (minimum SPF 30) application to all exposed skin areas, reapplication every 2 hours during sun exposure, and use of physical barriers including protective clothing and wide-brimmed hats 2, 4

The American Academy of Dermatology suggests treating patients at least 48 hours apart (preferably 72 hours) to allow assessment of photoreactions from previous treatment, with twice weekly treatments being standard and safer for PUVA therapy 1, 4
For NB-UVB therapy, three times per week on nonconsecutive days is the standard protocol, with twice weekly sufficing but clearing disease more slowly 4

High cumulative PUVA exposure increases squamous cell carcinoma risk 14-fold compared to low-dose PUVA, with 26% of patients on continuous PUVA maintenance developing non-melanoma skin cancer 5, 6
Melanoma risk increases after 15 years of PUVA exposure or with high cumulative doses, while NB-UVB shows no significant association with skin cancer at median 5.5 years follow-up 5, 6, 2