Sun-related skin diseases.

Severe photoaging of the skin, which may be caused by exposure to both natural and artificial ultraviolet light, ultimately results in actinic keratoses and cancer. Cancers are common on the head, neck, arms, and hands. Because of the potential for metastasis, squamous cell carcinomas generally require surgical excision and histologic examination. Although metastasis is rare with basal cell carcinoma, neglected lesions around the eyes, nose, or ears can invade bone, nerves, and cartilage and may cause death. Avoidance of sun, physical protection, and regular use of sunscreens are recommended.