The most common cause of actinic keratoses (pre-cancerous lesions that usually start to appear on fair-skinned people in their 50s) is sun exposure. Those who have worked outdoors or spent a significant amount of time engaging in outdoor recreational pursuits – such as sailing, golfing or skiing – are at greater risk of developing these sun-induced spots. Actinic keratoses are rough scaly patches of skin that are considered to be pre-malignant, and it left untreated, approximately 1% of these lesions become cancerous. Getting an adequate amount of vitamin D, either through a balanced diet or through supplements, is thought to provide some preventative benefits. Incorporating the use of a sunscreen into your daily skin care regimen and wearing protective clothing and accessories can limit the amount of UV damage to your skin. If you have noticed some suspicious skin changes, see your doctor for a confirmed diagnosis.