1. A medical diagnostic method comprising the steps of: providing a video camera; aiming said video camera at a skin surface of a patient; operating said video camera to generate a digitized video signal encoding an image of the skin surface of the patient; automatically analyzing said video signal to derive digitized data pertaining to visually detectable characteristics of the skin surface of the patient; automatically comparing the digitized data with data stored in an electronic memory to derive a diagnosis as to a skin condition of the patient; and communicating the derived diagnosis to a user.