Venous Ulcers

What causes venous ulcers?

Leg veins have one-way valves that keep blood moving up toward the heart, helped by the calf muscle squeezing the veins with each step. When the valves are damaged or the calf pump is weak, blood flows backward and pools. This chronic venous insufficiency raises pressure in the small vessels of the skin.

Over time, fluid, proteins and red blood cells leak into the tissue. Iron from the red cells stains the skin brown, inflammation hardens it, and the skin receives less oxygen. A small knock or scratch then breaks down into an ulcer that cannot heal.

Risk factors

• varicose veins
• a previous deep vein thrombosis, which can leave scarred valves (post-thrombotic syndrome)
• obesity
• older age
• long periods of standing or sitting
• reduced ankle movement or limited walking, which weakens the calf pump
• several pregnancies
• leg injury or surgery
• family history of vein disease

Symptoms and appearance

The ulcer

• usually on the inner side of the leg, above the ankle bone, though it can be anywhere on the lower leg
• shallow, with irregular, sloping edges
• red granulation tissue or yellow slough at the base
• produces moderate to heavy fluid, which can soak dressings
• often less painful than arterial ulcers, though it may ache or throb, and pain eases when the leg is raised

Changes in the surrounding skin

• swelling of the ankle and lower leg, worse at the end of the day
• brown or purple discoloration (hemosiderin staining)
• itchy, scaly, red skin (stasis dermatitis, also called varicose eczema)
• hard, tight, woody skin that narrows the lower leg like an inverted champagne bottle (lipodermatosclerosis)
• small white scar-like patches (atrophie blanche)
• visible varicose veins and small dilated veins around the ankle

Venous vs arterial and diabetic ulcers

Many people, especially older adults, have mixed venous and arterial disease. The diabetic foot ulcer page covers foot ulcers in diabetes.

How venous ulcers are diagnosed

• Examination of the ulcer, skin and leg, with measurement of the ulcer size.
• Ankle-brachial pressure index (ABPI): blood pressure is measured at the ankle and arm with a Doppler probe. This must be done before compression, because strong compression is unsafe if arterial blood flow is poor. A ratio of about 0.8 to 1.3 usually allows full compression.
• Venous duplex ultrasound: shows which veins are leaking and whether there are old clots.
• Wound swab only if infection is suspected.
• Biopsy of ulcers that look unusual or fail to heal, to rule out skin cancer.
• Blood tests for diabetes, anemia and nutrition.

Venous ulcer treatment

Compression therapy

Compression is the single most effective treatment. It squeezes the leg, supports the veins, reduces swelling and improves blood flow in the skin.

• Multilayer compression bandages applied by a trained nurse, changed once or twice a week.
• Compression wraps with adjustable Velcro straps that you can manage yourself.
• Compression stockings or ulcer hosiery kits once swelling is controlled.

Compression should be worn all day and is often uncomfortable at first. If it causes increasing pain, numbness, or toes that are cold or blue, remove it and contact your nurse.

Wound care

• clean the ulcer with water or saline at dressing changes
• remove dead tissue (debridement) when needed
• use simple, non-stick dressings matched to the amount of fluid
• protect and moisturize the surrounding skin. A steroid cream may be prescribed for eczema
• avoid products that commonly cause allergy, such as lanolin, fragrances and some antibiotic creams

Helping the calf pump

• Walk regularly. Walking pumps blood out of the legs.
• Ankle exercises: flex and point the feet and circle the ankles several times an hour when sitting.
• Raise your legs above heart level for 30 minutes 3 to 4 times a day, and raise the foot of the bed.
• Avoid standing still or sitting with legs down for long periods.

Treating infection

Infected ulcers (with spreading redness, heat, increasing pain, pus or fever) need antibiotic tablets, or IV antibiotics for cellulitis with systemic illness. Routine antibiotics or antiseptic creams on uninfected ulcers do not help healing.

Medicines

Pentoxifylline may be added to compression to speed healing in some people. Aspirin is not routinely recommended.

Vein procedures

Treating the underlying leaking veins, with endovenous laser or radiofrequency ablation or foam sclerotherapy, speeds healing and roughly halves the chance of the ulcer coming back. Guidelines recommend early referral to a vascular service for this.

Skin grafts

Large or stubborn ulcers may be treated with skin grafts or skin substitutes, alongside compression.

Healing time and recurrence

Many venous ulcers heal within 3 to 6 months with good compression. Large ulcers, long-standing ulcers and those with poor mobility or mixed arterial disease take longer. Up to about two thirds come back within a few years if compression stops, so lifelong compression stockings and vein treatment are key.

Preventing venous ulcers

• Wear compression stockings every day if you have venous insufficiency or have had an ulcer.
• Stay active and keep a healthy weight.
• Moisturize the lower legs daily and treat eczema early.
• Protect the legs from knocks and scratches.
• Get early treatment for varicose veins and any leg wound that does not heal within 2 weeks.

Frequently asked questions

What causes venous ulcers?

They are caused by chronic venous insufficiency. Damaged valves in the leg veins let blood flow backward and pool, raising pressure in the skin of the lower leg. The skin becomes swollen, stained, inflamed and starved of oxygen, so even minor injuries break down into ulcers.

How long do venous ulcers take to heal?

With good compression therapy and wound care, many heal in 3 to 6 months. Large or long-standing ulcers may take a year or more. An ulcer not healed after 12 weeks of proper treatment needs specialist review.

How do I tell a venous ulcer from an arterial ulcer?

Venous ulcers are shallow, moist and above the inner ankle, with swelling and brown skin, and feel better when the leg is raised. Arterial ulcers are deep, dry and punched-out on the toes or foot, very painful, and worse when the leg is raised. A Doppler test confirms the difference.

Can I wear compression with a leg ulcer?

Yes, compression is the main treatment for venous ulcers, but only after an ankle-brachial pressure index test confirms that arterial blood flow is adequate. Compression on legs with poor arterial supply can cause serious damage.

Do venous ulcers come back?

They often do, particularly if compression is stopped. Wearing compression stockings every day, treating the leaking veins with ablation or sclerotherapy, staying active and caring for the skin greatly reduce the chance of recurrence.