To determine the optimal treatment frequency of 308-nm excimer laser for vitiligo and identify the key clinical variable(s) associated with the treatment efficiency under the optimal treatment frequency.

Prospective, randomized, comparative study among groups of vitiligo patients treated with 308-nm excimer laser, with the limitation of no follow-up.

Vitiligo patients were treated with 308-nm excimer laser for 20 sessions at different frequencies (0.5×, 1.0×, 2.0× and 3.0× weekly). Treatment protocols adapted the dose to the lesions and not to the minimal erythemal dose. Treatment efficacy was blindly evaluated by 2 independent physicians. Re-pigmentation rate was graded on a 6-point scale. The onset of re-pigmentation of vitiligo lesions was evaluated after 5 treatment sessions. The differences between Group 0.5×, 1.0×, 2.0× and 3.0× linking different clinical variables were assessed.

Inclusion Criteria:

• older than 2 years, stable vitiliginous patches during the past 3 months with surfaces of at least 4cm2, and an understanding of all information given by signing a written consent form.

Exclusion Criteria:

• pregnant or breastfeeding women; personal history of a hypertrophic scar, skin cancer; taking immunosuppressive or photosensitizing drugs and undergoing phototherapy during the past 3 months.