What Is Venous Ulcer

  • Yelim Lee Master's degree, Clinical Drug Development, Queen Mary University of London, UK

Venous ulcers are breaks in the surface of the skin, which occur most commonly in the lower leg just above the ankles (the ‘Gaiter area’). They occur in people who suffer from venous insufficiency and are chronic, meaning that they do not heal for at least 2 weeks. 

In the UK, around 3 in 1000 people will suffer from venous ulcers. The incidence rises with age, and in people over the age of 80, as many as 20 in 1000 people can be affected.1

What are veins?

Blood is carried around the body by a network of blood vessels. Blood which has picked up oxygen in the lungs (oxygenated blood) is carried away from the heart in arteries, which are large, elasticated vessels. The blood in these vessels is under high pressure due to the pumping action of the heart. Arteries are divided into smaller vessels, called arterioles, and then into even smaller vessels, called capillaries. The walls of capillaries are very thin, allowing oxygen to diffuse out of the blood and into the cells. The blood which has given up oxygen into the tissues (deoxygenated blood) flows out of the capillaries into vessels called venules, which merge into larger vessels called veins. Unlike arteries, the flow of blood through veins is not caused by the pumping of the heart and is under a much lower pressure. In veins, the blood flow needs to occur against the force of gravity and is assisted by contractions of muscles surrounding the veins (for example, in the legs, the contraction of the calf muscles helps to push blood back up the veins away from the feet and ankles). Veins also contain a series of one-way valves that prevent blood from flowing back in the wrong direction. Deoxygenated blood is then returned to the heart and back to the lungs to pick up more oxygen, and the cycle of blood flow is repeated.

Chronic venous insufficiency

In people who develop chronic venous insufficiency (CVI), blood flow in the veins is disrupted, blood pressure within the veins increases, and blood pools within the veins. Due to gravity, this most commonly affects the veins in the legs. CVI can happen when the valves in the veins become weak or damaged or if there is a blockage further up the vein, such as a blood clot. Other factors which put a person at risk of developing CVI include obesity, leg injury and prolonged periods of immobility.

In patients with CVI, the increased pressure causes the vein walls to become damaged, and fluid and cells from the blood can leak from the veins into the surrounding tissues.2

Symptoms of chronic venous insufficiency.

  • Varicose veins 
  • Leg swelling
  • Skin changes such as discolouration and thickening of the skin
  • Eczema
  • Pain
  • Development of ulcers

How is a venous ulcer diagnosed?

Although venous ulcers are the most common type of ulcer that develops on the legs, there are other potential causes, and the way the ulcer is treated will depend on the underlying cause. It is important that you see a doctor to get the correct diagnosis and treatment.

If you develop an ulcer on your leg, a doctor will want to ask you questions and examine you to find out what has caused the ulcer to develop. 

What will a doctor want to ask me?

Important information that a doctor will need to know about you includes the following: how the ulcer developed (was there a skin injury?), how long it has been there, what symptoms you are experiencing (pain, itchiness and symptoms of infection), and whether you have ever had a leg ulcer before. Also, your medical history, any conditions that may increase your risk of developing an ulcer (such as diabetes, vascular disease, or autoimmune diseases like rheumatoid arthritis), and the details of any medications that you are taking will also be asked by the doctor. 

How is an ulcer examined?

The site and appearance of an ulcer are important factors in diagnosing the cause. Venous ulcers are most commonly found on the ankles and lower legs and are usually quite shallow and irregular in size and shape. There are often changes to the skin surrounding the ulcer, which show that the person is suffering from chronic venous insufficiency. The clinician will also look for any signs that the ulcer may be infected, such as discoloured fluid leaking from the ulcer, an unpleasant smell and redness around the edges of the ulcer.3

If you have developed an ulcer, a clinician will often want to examine the rest of your body to look for any other signs of illness which may lead to ulcers and to check for ulcers in any other locations.

What tests need to be carried out?

Blood tests

If you have developed an ulcer, you will usually need blood tests to look for any signs of infection and to check for underlying diabetes, as people with diabetes are more prone to developing ulcers. It is also important for your doctor to know if you are anaemic, as people with anaemia are more prone to having wounds which heal very slowly. 


Swabs will often be taken of any fluid that is leaking from an ulcer to look for bacteria, which may suggest that the ulcer is infected. This will also make sure that if there is an infection, the correct antibiotic is used to treat it.1

Doppler ultrasound

A Doppler ultrasound is an investigation which uses sound waves to detect the flow of blood through the blood vessels. In patients who have an ulcer, it is often used to make sure that the blood is still flowing properly through the arteries in the area affected. People who have diseases that affect the blood flow through the arteries can also develop ulcers, and these types of ulcers require different treatment than venous ulcers. It is also important because one of the methods used in managing venous ulcers is compression bandaging, but this type of bandaging cannot be used safely in people who have poor blood flow through the arteries.4

Treatment of venous ulcers

The main line of treatment for venous ulcers is specialist dressings and the use of compression bandaging

The ulcer and surrounding skin will be cleaned, and dead tissue will be removed by careful debridement. The type of dressing used on the wound will be decided by a specialist in dressings, usually a specialist nurse. The dressing should be non-adherent so that it does not stick to the ulcer. Other factors that determine the type of dressing used include the size and location of the wound, the amount of exudate (fluid) leaking from the wound, and any allergies the patient may have to certain dressing types. 

How often the dressing needs changing depends on how much fluid is leaking from the wound. The dressing should not be left saturated with fluid but should also not be allowed to become overly dry as this may cause it to stick to the wound and cause further damage when it is removed. A patient with dressings on a venous ulcer should be assessed regularly to determine if the dressing needs changing. 

Dressing changes can sometimes be painful, so a person who needs a dressing change will usually be given painkillers before the dressing is removed. 

Once the ulcer has been dressed, a compression bandage is often used to help the blood flow in the veins and prevent ongoing blood pooling. Compression bandages are tighter at the ankle and become gradually looser as they move up the leg. This type of bandaging aims to help squeeze blood through the veins away from the feet against the force of gravity. As with dressings, compression bandaging is applied by a specialist in dressing application.1,4

What if an ulcer becomes infected?

In cases where an ulcer is infected, a person will need antibiotics to treat this. The type of antibiotic used will depend on any bacteria that have been identified on swabs taken, the severity of the infection and any allergies the patient has to antibiotics. In some cases, where an ulcer has become badly infected, and the patients become very unwell, they may need to be admitted to the hospital for intravenous antibiotics and, in some severe cases, an operation to cut away infected and dead tissue at the site of the ulcer. 


What is an ulcer?

  • An ulcer is a sore which develops as a result of the surface layer of the skin eroding away, leaving the soft tissue underneath exposed. Ulcers can be superficial, affecting only the surface of the skin, or can be deep, extending into the soft tissues, muscles and, in severe cases, to the bone. There are numerous causes of ulceration, but 60-80% of leg ulcers will result from chronic venous insufficiency5 

What are veins?

  • Veins are blood vessels which carry deoxygenated blood away from the tissues and back towards the heart. Unlike arteries, which carry blood away from the heart under pressure due to the heart's pumping action, the pressure of blood in the veins is much lower, and the flow of blood in the veins is aided by contractions of the muscles which surround the veins. Many veins, particularly those in the legs, contain valves that prevent blood from flowing back in the wrong direction and from pooling in the lower parts of the body.

What is chronic venous insufficiency, and why does it occur?

  • Chronic venous insufficiency means that the blood flow in the veins of the legs is impaired, and as a result, blood pools in the veins. It occurs when the valves in the veins, which prevent the backflow of blood, become weak or are damaged. 


There are several different conditions which can lead to the development of ulcers. Venous ulcers are the most common type of ulcer. They are open sores  that appear usually  on the lower legs. As they are slow to heal, they require specialist management for dressings and compression bandaging.

The chance of developing a venous ulcer can be reduced by changes to your lifestyle. If you are overweight, weight loss is important as being overweight increases the risk of developing chronic venous insufficiency. 

People who suffer from CVI can reduce the risk of developing an ulcer with good skin care (moisturisation), sitting with their legs up, and using compression stockings to help increase blood flow in their veins. 


  1. Nelson A, Adderley U. Venous leg ulcers. BMJ clinical evidence [Internet]. 2016 [cited 2023];2016(1902). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4714578/ 
  2. Eberhardt RT, Raffetto JD. Chronic Venous Insufficiency. Circulation 2014;130:333–46. https://doi.org/10.1161/CIRCULATIONAHA.113.006898.
  3. Millan SB, Gan R, Townsend PE. Venous Ulcers: Diagnosis and Treatment. Afp 2019;100:298–305.
  4. Venous leg ulcer symptoms and treatments n.d. https://www.nhsinform.scot/illnesses-and-conditions/skin-hair-and-nails/venous-leg-ulcer (accessed October 6, 2023).
  5. Leg ulcer - venous [Internet]. 2023 [cited 2024]. Available from: https://cks.nice.org.uk/topics/leg-ulcer-venous/ 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.
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