The primary objective of this study is to get clinical experiences with the PALLAS laser in the treatment of skin conditions that respond well to UV light (vitiligo, psoriasis, alopecia areata, atopic dermatitis). The secondary objective is to assess how user-friendly is the Pallas laser in the treatment of skin diseases. The patient in the trial will receive UVB laser treatment (2 treatments per week for up to 3 months). The treatments will be carried out by the doctors participating in the trial. The treatment takes approximately 10 minutes per session, and can last up to 3 months per patient. Photographic documentation of the lesions to be treated and the lesions treated is taken at the start of the examination and then once a month. At the end of the study, the patient rates the treatment and improvement on a Patient Satisfaction Scale.