[Skin signs of systemic diseases].

Many aspects of cutaneous signs are of importance to nondermatologists, as skin manifestations can reflect internal disease states, either directly or as a result of a complication or treatment and therefore can lead to the diagnosis of systemic illness. Serious morbidity and mortality can be avoided by early recognition of only minor cutaneous manifestations signaling internal problems. Limited forms of collagen vascular disease exemplify the important marker function of the skin for diagnosis as well as for prognosis with their typically favorable course permitting a less aggressive treatment. The utmost important prerequisite of diagnosing skin conditions is an accurate and thorough examination of the skin, the adjacent mucous membranes and the integumentary appendages. In a first step, the primary site of the cutaneous condition should be identified (e.g. epidermal, dermal or subdermal) and then the form, the pattern, and distribution should be recognized. There are many comprehensive and excellent textbooks available for guidance. This article focuses on the more common dermatologic conditions linked to different organ systems involved (excluding infectious diseases, metabolic diseases and drug induced conditions).