Early and late radiation-induced skin alterations. Part I: Mechanisms of skin changes.

Early and late radiation-induced skin changes have been a concern of health professionals in radiation oncology since the early use of radiation to treat disease. Although the elicited skin reactions from solar exposure and ionizing radiation may appear to be similar, mechanisms of tissue injury are different. The time of onset, the duration, and the intensity of side effects related to radiation therapy are influenced by site of radiation field, time-dose-volume relationship, radiosensitivity of tissues in the skin, type and energy of radiation, nutritional status of the patient, adherence to skin management recommendations, and innate individual differences among patients. The effects of skin irradiation can be categorized as early and late reactions. When combined with radiation therapy, some chemotherapy agents as well as hyperthermia can enhance skin reactions.