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A skin ulcer is where an area of skin has broken down and you can see the underlying flesh. Ulcers which last for years together are often caused by problems with veins or arteries. Other causes may include skin cancer, dermatological conditions, some immune system problems and trauma.
Venous leg ulcers are the most common type of skin ulcer. They mainly occur just above the ankle. Risk factors for vein problems include: people who require to stand long durations, while working ; Varicose veins ;Past history of DVT or blood clot in the veins. Conditions like diabetes, parasitic infections also need to be ruled out.
To know the exact cause of the ulcers, you might consult with your doctor and undergo a few tests including doppler ultrasound of the lower limb veins or a angiogram, which will confirm the cause of the ulcer. A biopsy of the ulcer might also be important.
The most important part of treatment is would be wound dressing and antibiotics to clear any infections. Limb elevation (while resting) and use of compression bandages will be helpful to prevent venous stasis. Skin graft or vein surgery may be resorted to if the blood supply of the area is intact. After the ulcer has healed you should wear a support stocking each day which helps to prevent it recurring.
I hope the information helps.