Efudex is used to treat actinic keratoses. An actinic keratosis is a precancerous skin lesion caused by sun damage. Actinic keratoses feel rough and are sometimes scaly. Actinic keratoses are not skin cancer, but they often turn into skin cancer. The sun damage responsible for an actinic keratosis has usually occurred years before the lesion forms.
Sun damage is permanent and irreversible.
You should put on sun-screen or moisturizer with an SPF of 15 or higher every day before leaving the house. The medication is applied to the involved area twice a day. This is continued for five to six weeks, depending on the response. The treated area becomes red, raw and irritated. Healing starts when the Efudex is stopped.