Description: A close-up, showing the thin border.

History: This 57 years old lady complains of leg and arm lesions: they appear each summer when she spends much time outside bicycling. They are red and a bit itchy, and their number increases each year. They don't disappear completely during the winter. The exam reveals numerous small and well delimitated lesions small to middle size macules. Some of them seem irritated. It's a typical history and aspect of a Disseminated Superficial Actinic Porokeratoses.