Actinic damage among patients with psoriasis treated by climatotherapy at the Dead Sea

Abstract

Dead Sea climatotherapy is highly effective in the treatment of psoriasis. However, its potential side effects, especially the risk of skin cancer, are unclear. We sought to determine the prevalence of solar damage and skin cancer among patients with psoriasis who underwent Dead Sea climatotherapy compared with control patients. This multicenter controlled cross-sectional study was carried out at the Dead Sea Solarium Clinic and outpatient clinics of the participating centers. A total of 1198 participants (460 patients with psoriasis and 738 control patients) aged 20 to 70 years were included. A standard questionnaire including demographic parameters and sun exposure habits was administered to all participants. Patients were questioned about previous psoriatic treatments and climatotherapy at the Dead Sea. All participants underwent a structured physical examination of the skin. We compared the prevalence of solar damage for patients with psoriasis and control patients and assessed the extent of photodamage among patients with psoriasis according to exposure time at the Dead Sea in univariate and multivariate analyses. Elastosis ( P < .001), solar lentigines (P = .03), poikiloderma (P < .001), and facial wrinkles (P < .001) were significantly more common among patients with psoriasis compared with control patients and showed a dose response with increased Dead Sea exposure time. Self-reported previous skin cancers were more common in control patients compared with patients with psoriasis (8.2% vs 3.5%, P = .002), however, the prevalence of nonmelanoma skin cancer on examination did not differ between the two groups. No cases of malignant melanoma were detected in either group. Dead Sea climatotherapy is not associated with an increased risk of malignant melanoma or nonmelanoma skin cancer for patients with psoriasis in Israel. However, UV exposure at the Dead Sea may play a role in the development of solar damage.