ConditionSkin, hair & nails
Wound Healing Problems (Slow-Healing and Chronic Wounds)
Wound healing problems occur when a cut, sore, ulcer or surgical wound heals much more slowly than expected or stops healing. Most healthy wounds close within 2 to 4 weeks; a wound that has not improved in 4 weeks, or healed in about 3 months, is considered chronic. Common causes are diabetes, poor circulation, venous insufficiency, pressure, infection, smoking, poor nutrition and some medicines. Treating the underlying cause, keeping the wound clean and moist, and specialist wound care heal most chronic wounds.
Also called: Impaired wound healing, delayed wound healing, chronic wounds, non-healing wounds, slow-healing sores
At a glance
- What it is
- A wound that is healing slowly or has stalled.
- Chronic wound
- No improvement after about 4 weeks, or not healed after about 3 months.
- Common types
- Diabetic foot ulcers, venous leg ulcers, arterial ulcers, pressure injuries, non-healing surgical wounds.
- Main causes
- Diabetes, poor circulation, swelling, pressure, infection, smoking, malnutrition, steroids, radiation.
- Warning signs
- Spreading redness, pus, odor, increasing pain, black tissue, fever.
- Treatment
- Treat the cause, clean and debride, moist dressings, compression or offloading, infection control, specialist care.
When to get help
Call 911 or go to the ER
- A wound with rapidly spreading redness, severe pain, blistering, gray or black skin, or crackling under the skin (possible necrotizing infection): call 911 or your local emergency number
- Fever with confusion, fast breathing or feeling very unwell with an infected wound (possible sepsis)
- A foot or leg that is suddenly cold, pale and painful
See a doctor within a day or two
- Signs of infection: spreading redness, warmth, swelling, pus, a bad smell or red streaks
- A foot wound, blister or color change in someone with diabetes
- A surgical wound that is opening up or leaking a lot of fluid
- Black or dead-looking tissue in or around a wound
Book a routine appointment
- A wound that has not improved in 2 weeks or healed within 4 weeks
- A leg ulcer with swelling, varicose veins or brown skin around the ankle
- Pain in the legs when walking with a sore on the foot or toes
- Red or broken skin over the hips, heels or tailbone in someone who sits or lies for long periods
How normal healing works
Healing happens in overlapping stages: stopping bleeding, inflammation (clearing bacteria and debris), rebuilding (new tissue and blood vessels fill the wound) and remodeling (the scar strengthens over months). Any factor that disrupts blood supply, oxygen, nutrients, immunity or the wound environment can stall healing, often in the inflammatory stage.
Common types of chronic wounds
| Wound type | Typical location | Clues |
|---|---|---|
| Diabetic foot ulcer | Soles, toes, pressure points | Numb feet, calluses, may be painless |
| Venous leg ulcer | Inner ankle, lower leg | Swelling, varicose veins, brown skin, aching relieved by elevation |
| Arterial ulcer | Toes, heels, shins | Painful, punched-out, cold pale foot, weak pulses |
| Pressure injury | Tailbone, hips, heels | Immobility; ranges from red skin to deep wounds |
| Surgical wound breakdown | Incision | Infection or wound dehiscence |
Causes of poor wound healing
Local factors
- Infection: bacteria and biofilm prevent healing. See wound infection.
- Poor blood supply: peripheral artery disease starves tissue of oxygen.
- Swelling and venous insufficiency.
- Pressure, friction and repeated trauma.
- Dead tissue or foreign material in the wound.
- Wound too dry or too wet.
Whole-body factors
- Diabetes: high blood sugar impairs immune function, circulation and nerves.
- Smoking: reduces oxygen delivery and constricts blood vessels.
- Poor nutrition: low protein, calories, vitamin C or zinc (malnutrition).
- Older age.
- Obesity.
- Medicines: corticosteroids, chemotherapy, immune suppressants and some biologics.
- Radiation therapy to the area.
- Kidney and liver disease, anemia, heart failure.
- Immobility.
Rarely, a non-healing wound is a skin cancer or caused by inflammatory conditions such as pyoderma gangrenosum or vasculitis, which is why biopsy is sometimes needed.
Signs a wound is not healing well
- no reduction in size after 2 to 4 weeks
- increasing pain, redness or swelling
- pus, cloudy or increasing discharge, or a bad smell
- edges that are rolled, thickened or undermined
- yellow slough or black dead tissue
- bleeding easily or fragile, dark red tissue
- fever or feeling unwell
Diagnosis
A doctor or wound specialist will assess the wound's size, depth, tissue and edges, and look for the cause:
- blood sugar and HbA1c, blood count, kidney function, albumin and nutrition markers
- ankle-brachial index and Doppler ultrasound to check arterial blood flow
- venous duplex ultrasound for venous disease
- wound swabs or tissue cultures for infection
- X-ray or MRI if bone infection (osteomyelitis) is suspected
- biopsy of wounds that look unusual or have not healed after about 3 months
Treatment
Treat the underlying cause
- improve blood sugar control
- restore blood flow with angioplasty or bypass in arterial disease
- compression bandages or stockings for venous ulcers (only once arterial disease is excluded)
- offloading pressure with special footwear, casts or pressure-relieving mattresses
- stop smoking
- improve nutrition, especially protein
- review medicines
Wound care
- Cleaning with saline or water at each dressing change.
- Debridement: removing dead tissue, by a clinician, to stimulate healing.
- Moist wound healing: modern dressings (foams, hydrocolloids, alginates, hydrogels) keep the right moisture balance.
- Infection control: antimicrobial dressings and antibiotics for clinical infection.
- Advanced therapies: negative pressure wound therapy (wound vacuum), skin substitutes, grafts, growth factors, and hyperbaric oxygen for selected diabetic foot ulcers.
Wound care centers
Multidisciplinary wound clinics bring together nurses, podiatrists, vascular surgeons and other specialists for complex wounds.
Prevention
- Check feet daily if you have diabetes or neuropathy.
- Change position at least every 2 hours if bed-bound; use pressure-relieving cushions and mattresses.
- Keep skin moisturized and protected.
- Wear well-fitting shoes.
- Treat swelling with elevation and compression if advised.
- Do not smoke.
- Clean and cover cuts promptly.
Frequently asked questions
Why is my wound not healing?
Common reasons include infection, poor blood flow, swelling, pressure on the area, diabetes, smoking, poor nutrition, older age and medicines such as steroids. A clinician can identify the cause with an examination and simple tests and adjust treatment.
How long should a wound take to heal?
Small, healthy cuts usually heal in 1 to 2 weeks, and most wounds within 2 to 4 weeks. A wound that has not started improving within 2 to 4 weeks, or is not healed after about 3 months, is considered chronic and should be assessed.
What helps a slow-healing wound heal faster?
Keep it clean and moist with an appropriate dressing, relieve pressure, raise swollen legs, eat enough protein, control blood sugar, and stop smoking. Treating infection and improving circulation are often essential. A wound care specialist can add advanced treatments.
When is a non-healing wound serious?
It is serious if there are signs of spreading infection, black tissue, a bad smell, fever, or if you have diabetes or poor circulation. A wound that has not healed in 3 months should be checked, including sometimes a biopsy to rule out skin cancer.
Sources
This guide was written from current patient and clinical guidance, including:
- American Diabetes Association: Standards of Care in Diabetes, foot care
- Wound Healing Society: Guidelines for the treatment of chronic wounds
- National Pressure Injury Advisory Panel: Prevention and treatment of pressure ulcers/injuries
- Society for Vascular Surgery: Venous leg ulcer guidelines
- MedlinePlus: Wounds and injuries