While effective, some people should avoid excess ultraviolet radiation -- natural or synthetic -- for the treatment of their psoriasis. These people include:
- patients with light sensitive diseases, including but not limited to lupus or porphyria
- patients with a history of melanoma or invasive squamous cell carcinomas of the skin (skin cancer)
- Patients who have had their eyes' natural lenses removed due to cataracts, since the lens protects the retina against UV radiation
- women who are pregnant
Special care should be taken when using ultraviolet radiation to treat patients who have a history of basal cell carcinoma of the skin, arsenic exposure, or a history of prior x-ray therapy.