Related Experiment Video
Updated: Jun 22, 2026

Studying Chronic Exposure of Mice to Ultraviolet B Radiation
Published on: August 19, 2025
Granulomatous slack skin responds to UVA1 phototherapy
Patrick A Oberholzer1, Antonio Cozzio, Reinhard Dummer
1Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
Abstract:
Granulomatous slack skin (GSS) is an extremely rare disorder within the group of cutaneous T cell lymphomas (CTCL). Ultraviolet A1 (UVA1) phototherapy has previously been reported to be useful in the treatment of CTCL such as mycosis fungoides. We report a 35-year-old Caucasian male with GSS treated with UVA1 phototherapy starting at 20 J/cm(2) UVA1 3 times a week and subsequently increased in increments of 5 J/cm(2) to a medium-range dose of 50 J/cm(2) per session. The patient underwent a total of 45 sessions with a cumulative dose of 1,495 J/cm(2) UVA1 without any adverse events. At the conclusion of UVA1 phototherapy, a decrease in erythema and skin thickness was observed which was most prominent in the periphery of the lesion in the right groin area. A follow-up 12 months after phototherapy showed continued treatment benefit. To our knowledge, this is the first report describing the successful use of UVA1 (340-400 nm) phototherapy in a patient with GSS.
Related Concept Videos
Acne Infection
Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
Changes in Skin Color: Clinical Perspectives
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Skin Diseases and Disorders
Gram-positive Staphylococcus spp. and Streptococcus spp. are responsible for many of the most common skin infections. However, many...
Skin Cancer
Basal Cell Carcinoma (BCC): BCC is the most common type of skin cancer, accounting for about 80% of cases. It typically develops in...
