From our glossary, in historical perspective, it becomes obvious that imprecision in terminology has become a serious impediment to comprehension of a disease process. The usage of the same term for findings clinical on one hand and for a distinct disease entity on the other, such as was the case with atrophie blanche, and the application of different terms to one and the same feature clinical, such as with livedo reticularis and livedo racemosa both being applied to a branched pattern of livedo, have confused students of the subject over decades. Rarely have authors made an attempt to define with precision new terms that they introduced, e.g., livedoid vasculitis, or livedo vasculopathy. Regional variation in definition and usage of terms has complicated matters even further especially when authors tried to review literature written in another language than their own mother tongue (which they rarely did). Selected quotations from the literature of dermatology and dermatopathology that follow at the end of this article illustrate beautifully the jumble in communication.

In order to clarify terminology, we have made a distinction into I) useful terms, II) confusing terms, and III) antiquated terms. We are aware, however, that even the terms that we have identified as "useful" are not really precise in regard to their original meaning (e.g., livedo being applied to purpuric lesions when it designates literally, a pale blue color) and some of those that we have designated "confusing" may be of some value temporarily because they convey, even though imprecisely, a certain observation made by authors (e.g., the term "Sneddon syndrome" stands for the observation of livedo racemosa appearing together with neurologic signs and symptoms, and the designation "livedo vasculopathy" intends to convey that the condition termed livedo vasculitis may appear consequent to disorders of the coagulation cascade).