Chronic Wounds (Non-Healing Wounds)

How normal wound healing works

A healthy wound heals in overlapping stages: bleeding stops (hemostasis), inflammation clears debris and bacteria, new tissue and blood vessels grow (proliferation), and the scar strengthens (remodeling) over months. A chronic wound gets stuck, usually in the inflammatory phase, because something keeps damaging the tissue or starving it of oxygen and nutrients.

Main types of chronic wounds

Venous ulcers are the most common type of leg ulcer.

Why a wound will not heal

• Poor blood flow: narrowed arteries deliver too little oxygen.
• Venous hypertension: high pressure in veins causes swelling and tissue damage.
• Diabetes: high blood sugar impairs immune cells and healing; nerve damage means injuries go unnoticed.
• Continued pressure or friction.
• Infection and biofilm, a slimy layer of bacteria that resists treatment.
• Swelling (edema) and lymphedema.
• Poor nutrition: too little protein, calories, vitamin C or zinc.
• Smoking, which constricts blood vessels.
• Medicines such as long-term steroids, some chemotherapy and immunosuppressants.
• Older age, immobility, kidney disease and anemia.

Signs of infection in a chronic wound

• increasing pain
• spreading redness, warmth or swelling
• pus or increased discharge
• a new or stronger foul odor
• the wound getting larger or breaking down
• fragile tissue that bleeds easily
• fever and feeling unwell

Infection can spread to the surrounding skin (cellulitis) or to the bone (osteomyelitis), particularly under diabetic foot ulcers.

Diagnosis

A clinician will measure the wound, assess its base, edges and discharge, and look for the underlying cause:

• Ankle-brachial index (ABI): compares blood pressure at the ankle and arm to check arterial circulation. It is essential before compression therapy
• Duplex ultrasound of veins or arteries
• Blood tests: blood sugar and HbA1c, blood count, kidney function, albumin and inflammation markers
• Wound swab or tissue culture if infection is suspected
• X-ray or MRI to check for bone infection
• Biopsy of wounds that look unusual or have not healed after 3 months of good care, to rule out skin cancer or other causes

Treatment

Treat the underlying cause

• Venous ulcers: compression bandages or stockings are the cornerstone, along with leg elevation and sometimes vein procedures.
• Diabetic foot ulcers: offloading pressure with special casts, boots or footwear; tight blood sugar control; regular podiatry.
• Pressure ulcers: frequent repositioning, pressure-redistributing mattresses and cushions.
• Arterial ulcers: restoring blood flow with angioplasty, stents or bypass surgery. Compression must be avoided.

Wound bed care

• Cleaning with saline or water at each dressing change.
• Debridement: removing dead tissue and biofilm, by a clinician using instruments, special dressings, or other methods.
• Moist wound healing: modern dressings keep the wound moist but not wet, protecting surrounding skin.
• Managing infection with antibiotics when there are clinical signs, and antiseptic dressings where appropriate.

Advanced therapies

Negative pressure wound therapy, skin substitutes, skin grafts and hyperbaric oxygen therapy are used for selected wounds in specialist centers.

General measures

• stop smoking
• eat enough protein and calories; see a dietitian if needed
• control blood sugar and treat anemia
• stay as mobile as possible, and elevate swollen legs

Prevention

• check feet daily if you have diabetes or poor circulation, and see a podiatrist regularly
• wear well-fitting shoes and never walk barefoot with neuropathy
• wear compression stockings as advised after a venous ulcer heals, to prevent recurrence
• reposition regularly if bedbound, and keep skin clean and moisturized
• treat small wounds promptly

Frequently asked questions

What is a chronic wound?

A chronic wound is one that has not progressed through normal healing within about 4 weeks, or has not healed within 3 months. Common examples are venous leg ulcers, diabetic foot ulcers, pressure ulcers and arterial ulcers.

Why is my wound not healing?

Common reasons include poor blood circulation, high pressure in leg veins, diabetes, ongoing pressure on the area, infection, swelling, poor nutrition, smoking and certain medicines. Finding and treating the underlying cause is key to healing.

How do you tell if a chronic wound is infected?

Signs include increasing pain, spreading redness, warmth, swelling, pus, a stronger smell, the wound getting bigger, and fever. People with diabetes may have little pain, so changes in appearance or odor matter. See a clinician promptly.

Can chronic wounds be cured?

Most can heal with the right treatment of the underlying cause and good wound care, though it can take weeks to months. Ongoing prevention, such as compression after venous ulcers or foot care in diabetes, reduces the risk of recurrence.