Different Applications of Monochromatic Excimer Light in Skin Diseases

Background: Ultraviolet radiation has been used for curative purposes in dermatologic conditions, especially in the last 30 years. Objectives: We analyzed the efficacy of monochromatic excimer light in psoriasis, palmoplantar pustulosis, vitiligo, mycosis fungoides and alopecia areata, and to examine potential new indications. Methods: Two hundred seventy-nine patients with common and persistent skin diseases were enrolled in an open prospective study: 152 patients with stable and localized plaque psoriasis, 47 with palmoplantar psoriasis, 7 with palmoplantar pustulosis, 32 with vitiligo, 11 with prurigo nodularis, 9 with mycosis fungoides stage Ia, 8 with alopecia, 5 with localized scleroderma, 5 with genital lichen sclerosus, and 3 with granuloma annulare. The 308nm excimer light was used at a power density of 48mW/cm(2). An average of 12 sessions (range, 6-18), one session per week, was performed and yielded a total dose range of 4-12.5J/cm(2). Clinical response was assessed using photos, biopsies, and specific clinical scores. Patients were monitorized for 6 and 12 months for psoriasis, 12 months for mycosis fungoides, and 4 months for the remaining conditions. Results: We observed complete remission in more than 50% of patients with plaque psoriasis and palmoplantar dermatoses, respectively, complete remission in all patients affected by mycosis fungoides, excellent repigmentation in one third of vitiligo patients, hair regrowth in three patients with alopecia areata, an overall improvement in prurigo nodularis, a partial remission in patients affected by localized scleroderma, and a complete remission in most of the patients with genital lichen sclerosus and granuloma annulare. Conclusions: Our study confirms the use of monochromatic excimer light as a valid choice for the treatment of psoriasis, vitiligo, and mycosis fungoides; we also observed and report for the first time that monochromatic excimer light produces a therapeutic response in prurigo nodularis, localized scleroderma, genital lichen sclerosus, and granuloma annulare.