Actinic, or solar, keratosis is caused by chronic ultraviolet-induced damage to the epidermis. In the UK, 15-23% of individuals have actinic keratosis lesions. Dermatoscopy can be helpful in excluding signs of basal cell carcinoma when actinic keratosis is non-keratotic. It is always important to consider the possibility of squamous cell carcinoma. The principal indication for referral to secondary care is the possibility of cutaneous malignancy. However, widespread and severe actinic damage in immunosuppressed patients also warrants referral.