Evaluation of a novel 308-nm monochromatic excimer light delivery system in dermatology: a pilot study in different chronic localized dermatoses

Abstract

Recently, units have been developed that are capable of delivering large fluences of narrowband ultraviolet (UV) B selectively to cutaneous lesions within a reasonable time. To analyse the efficacy of a novel nonlaser 308-nm monochromatic excimer light (MEL) delivery system in various dermatoses usually treated by narrowband UVB phototherapy. Fifty-four patients with chronic and resistant localized dermatoses were enrolled in a prospective study: 17 with palmoplantar pustular psoriasis, seven with plaque-type psoriasis, four with nail psoriasis, eight with chronic atopic dermatitis of the hands, 10 with chronic nonatopic dermatitis of the hands and eight with alopecia areata. The 308-nm xenon chloride MEL delivery system (Excilite; DEKA, Florence, Italy) was used to produce an average incident dose rate of 50 mW cm(-2) at a tube-to-skin distance of 15 cm and with a maximum irradiating area of 512 cm2. The initial dose was based on multiples of a predetermined minimal erythema dose (MED), and subsequent doses were based on the response to treatment. Treatments were scheduled weekly for a maximum of 10 weeks. Clinical responses were evaluated using photographic documentation and (except for alopecia areata) clinical score. The MED ranged from 250 to 350 mJ cm(-2) (mean +/- SD 318.2 +/- 28.4). MEL at 308 nm was the most effective for palmoplantar pustular psoriasis with a mean improvement of 79% after a mean of 5.3 treatments and a mean dose of 11.8 MED per treatment. Plaque-type psoriasis was significantly less sensitive to treatment and nail psoriasis demonstrated no benefit from treatment. Chronic palmar atopic dermatitis was cleared in two patients and the mean improvement was 54% as compared with 46% in patients with chronic nonatopic dermatitis of the hands. Four complete regrowths among the eight patients with alopecia were observed after a mean of 5.1 treatments. The percentages of improvement had significantly decreased at the 6-month visit, and only four patients (24%) with palmoplantar pustular psoriasis still demonstrated a significant improvement. Common side-effects included intense erythema and, more rarely, blisters, but these were well tolerated. Our preliminary results confirm the efficacy of this novel 308-nm MEL delivery system, which appears to be effective and safe for palmoplantar pustular psoriasis. To a lesser extent, plaque-type psoriasis, chronic atopic and nonatopic dermatitis of the hands and alopecia may also benefit from this treatment.