[Differential ulcus cruris diagnosis].
Most leg ulcers are of venous or arterial origin (85%). Advanced chronic venous insufficiency is the most common underlying condition (65%), followed by advanced peripheral arterial occlusive disease (10%), and combined chronic venous insufficiency and peripheral arterial occlusive disease (10%). Chronic ulcers in diabetic feet (5%) are of great socio-economic importance, as well. They are a consequence of diabetic polyneuropathy which in part of the patients may be combined with peripheral arterial occlusive disease, usually of the calf arteries. However, a leg ulcer can also be caused by a large array of other underlying conditions, such as ulcerating skin tumours, trauma followed by disturbed wound healing, infectious ulcerations, ulcerations in angiodysplasias, vasculitic ulcerations, pyoderma gangrenosum, cholesterol-embolism, idiopathic livedo reticularis with ulceration, primary and secondary antiphospholipid-antibody-syndrome, coumarin-necrosis, calciphylaxis in chronic renal insufficiency, necrobiosis lipoidica, different forms of panniculitis, hematologic disorders, autoimmun diseases and autoimmun-bullous dermatoses. The following article discusses the differential diagnosis, examination and treatment of leg ulcers in these less common underlying conditions.