Photochemotherapy Photochemotherapy (PUVA) is a treatment for dermatological disorders that involves oral or topical application of photosensitizers followed by long-wave ultraviolet (UVA) (320-400 nm) irradiation. Systemic PUVA therapy is indicated for generalized vitiligo or for those who have failed to respond to topical treatment. there are some potential problems with the application of PUVA in children and therefore it is not recommended for children under 12 years of age. the dose of UVA is determined by the skin pigmentation depth and sensitivity to light. Generally oral 8-Methoxazole (8-MOP) 0.5mg/kg, 1.5~2 hours followed by UVA irradiation or sun exposure, 2~3 times a week, generally for more than 3 months. This therapy requires avoiding sunlight and wearing goggles for 12~24 hours during and after treatment. Topical PU-VA therapy is suitable for limited vitiligo with small lesions and small numbers. The topical application of 0.1%~0.2% 8-MOP tincture on the white spots, 0.5~1 hour after irradiation with UVA or sunlight, 2~3 times a week. It is believed that the efficacy of PUVA on vitiligo varies from person to person, and the pigment recovery of lesions on the face and neck is faster for short duration of disease, while the pigment recovery of lesions on the distal parts such as hands and feet and lips is poorer for long duration of disease. The efficacy of children patients is generally better than that of adults.