The effect of narrowband ultraviolet B phototherapy on serum folate level

BACKGROUND: Narrowband ultraviolet B (NB-UVB) phototherapy has been used as a common treatment for dermatologic diseases such as psoriasis and vitiligo and generally considered a safe form of therapy during pregnancy. Invitro photodegradation of folate after exposure to UVB radiation has been documented but studies on UVB-induced alternation of serum folate level have reported inconsistent results. The aim of this study was to investigate the effect of NB-UVB radiation on serum folate level. METHODS: In this study, serum folate levels were evaluated in patients at baseline and after 30 sessions of NB-UVB irradiation. RESULTS: Twenty patients completed the study: 10 psoriasis, 7 vitiligo and 3 mycosis fungoides (patch stage). Mean serum folate level had significantly decreased from 2.76±0.59 ng/ml at baseline to 1.34±0.15 ng/ml after 30 sessions. (Mean NB-UVB cumulative dose 40.35±16.80 j/cm(2), P=0.001). CONCLUSION: Serum folate levels may decrease after long-term NB-UVB phototherapy in patients with skin disorders.