Actinic keratoses are precancerous lesions that appear as subtle, rough spots found on sun-exposed skin. They commonly occur in fair-complected people fifty and over. Today, we are seeing many patients in their 30s with these precancerous lesions. If left untreated, up to 10% may become squamous cell skin cancers. Actinic keratoses are one of the most common conditions that dermatologists treat, using liquid nitrogen to spot-treat specific lesions. A more global approach is to treat the entire face or scalp by applying topical 5-fluorouracil or with Blue U light and topically applied Levulan (photodynamic therapy)..