By John E. Harris, MD, PhD and Mark Scharf, MD
The success of narrowband UVB (311-312) therapy for vitiligo was first reported by Westerhof and Nieuweboer – Krobotova in 1997. Yones et al. reported superiorefficacy of nbUVB over PUVA in 2007.
No evidence – based guidelines for treatment have been reported, and current protocols are based on experience. In general, a safe, aggressive treatment protocol is preferred to a conservative onefor two reasons:
1) Slow progression wastes time for the patient, who is eager to find the dose that will induce repigmentation.
2) Slow progression encourages light adaptation in the skin, which blocks UV penetration and the beneficial effects, possibly prolonging the time it takes to reach a therapeutic dose.
UV light treatment frequency should be 2-3x/wk. In two separate studies comparing 2x/wk vs. 3x/wk for vitiligo (Excimer laser) and psoriasis (nbUVB), 3x/weekly produced faster results than 2x/weekly, however eventually the two schedules resulted in equivalent efficacy. Therefore, if the patient’s schedule allows, I recommend starting at 3x/weekly for the first 3 months, and then decreasing to 2x/weekly thereafter.
A slight pink erythema lasting less than 24 hrs is thought to be an optimal response, which will occur at different light doses in different patients. The recommended starting dose for non-vitiligo treatment protocols is typically 50-70% of the MED assessed for each patient. Assessing MED for vitiligo is difficult due to limited involved skin, and arguably unnecessary since depigmented skin is similar to Type I skin, for which the average MED is 400. Therefore most protocols in use recommend basing the starting dose on this standard. Recommendations for increases at each visit are typically 5-20% of the previous dose, however many use a set dose increase that falls within this range for early treatments. Some protocols recommend soft holding doses, ranging from 500–3000 mJ/cm(1000 for face), however others have no set limits and have reportly used up to 5000 mJ/cm. There have been no reports of increased skin cancer risk using nbUVB (unlike PUVA), and therefore there are currently no recommendations for maximum number of treatments. How Does Phototherapy Work you can read here: https://uvb-lamps.com/blog/how-does-phototherapy-work/.
Shielding of sensitive anatomic sites is recommended by most protocols. A single study reported an increased cancer risk of nbUVB to male genitals, and therefore shielding of male genitals during treatment is recommended. Because female genitals are typically not exposed during treatment, shielding is not required.
UVB has been implicated in the formation of cataracts, and therefore shielding with UVB-protective goggles is standard practice, however this prevents Treatment of eyelids,with unsatisfactory results. Occasionally patients will be allowed to keep their eyes closed without goggles to exposethe eyelids when necessary.
Recent advances in contact lenses demonstrate the ability of Class I (Senofilcon A) soft contact lenses to block > 99% UVB light and protect rabbit cornea from adverse effects. Therefore, we will allow our patients with periocular depigmentation to wear Class I soft contact lenses in place of goggles during the beginning of each treatment session. Eyelids will be evaluated for erythema separately from the rest of the body, replacing goggles for the remainder of the session once “eyelid dose” appropriate for the patient has been reached. The first UMass protocol for nbUVB treatment of vitiligo (pre-2012) recommended a 200 mJ/cm starting dose, increasing by 50 mJ/cm at each visit; missed visits resulted in a dose decrease by 50% after 1-2 weeks or starting over after that. The following protocol was adapted by surveying other dermatology treatment centers (Henry Ford, UPenn), reviewing the methods for nbUVB efficacy studies in the literature, and from the current edition of Phototherapy Treatment Protocols. The current protocol willaim for mild erythema lasting 24-48hrs, based on updated recommendations. These guidelines are subject to change, and suggestions for modification are welcome.
Article is given for guidance only. In no case did not recommendations!
Full article can be read here http://www.umassmed.edu/globalassets/vitiligo/umass-uvb-phototherapy-guidelines.pdf