Venous Ulcers
Venous ulcers constitute 90% of the ulcers seen in a busy specialist clinic. It has been estimated that approximately 1% of the population will suffer from a leg ulcer at some stage during their lives. In a nation of 56 million people that is a lot of ulcers and the strain upon the National Health Service is considerable. Many people who have venous ulcers have obvious associated varicose veins like the person whose legs are shown the picture below.
It is this association that worries a lot of patients who have varicose veins that they are going to go on and develop an ulcer that will take months to heal. However, varicose veins are far commoner than ulcers so not everybody gets one; why is this? It all depends on the efficiency of the muscle pump and the veins themselves to drain the blood back to the pelvis and onwards to the heart. If these mechanisms become overwhelmed by torrential flow down the veins as the result of faulty valves the pressure in the veins rises. Normally the pressure in the veins goes down when we walk but a chronic rise in pressure as the result of too much of the blood coming back as the muscles relax results in an accumulation of fluid in the tissues of the leg, damage to the delicate venous capillaries draining into the larger veins and therefore leakage of blood and plasma into the tissues.
This is evident in the picture shown on the left. Tissue fluid can be seen pouring out of the ulcer. Blood and plasma contain enzymes and chemicals responsible for inflammation and the skin and underlying fat become itchy, swollen and sore. the clotting factor fibrinogen which also leaks out is turned to insoluble fibrin which is laid down in large amounts over time. The fibrin is gradually replaced by dense scar tissue. Scar tissue contracts (which is why scars from cuts gradually fade and become less prominent with age) and if the process goes on unchecked the tissues get choked up with the fibrous strands of the scar which doesn't have a rich blood supply. The fat under the skin becomes shriveled and thin and the skin loses much of its support. The skin in the area becomes vulnerable to trauma and breakdown into an ulcer. 
Once established, the ulcer will never heal unless the chain of events which led to it are reversed. The skin in the early stages of this process, and surrounding an established ulcer, takes on a patchy brown stain which is due to an insoluble breakdown product of the red cells that escaped into the tissues through the capillaries. It is called haemosiderin. In the picture above the ankle area shown shows this feature along with prominent veins and loss of the fat around the gaiter area (the so-called Champagne bottle leg!!) The skin over the ankle bone is blanched and white showing that its blood supply is not top quality. Care and attention to prevent trauma and measures to improve the muscle pump is required here to prevent yet another ulcer and months of misery healing it.