In short. The phases of wound healing, the difference between an acute and a chronic wound, and the four reasons a wound stalls: pressure, poor perfusion, infection, and uncontrolled diabetes.
Key points
- A chronic wound that closes over three to six months of consistent care is a success, not a failure.
- Progress is judged by measured area, depth, and tissue quality week by week — not by how the wound looks on any single day.
- Expecting a venous ulcer or a diabetic foot wound to close in a fortnight leads people to abandon treatment that was in fact working.
A wound is a break in the continuity of the skin, and the body treats it as an emergency. Within minutes, platelets plug the defect and release signals that summon inflammatory cells. Over the following days and weeks a carefully sequenced programme of clearing and rebuilding is meant to close the gap. Understanding that programme explains both why most wounds close and why some never do.
The phases of healing
Healing runs through haemostasis, inflammation, proliferation, and remodelling. Haemostasis stops the bleeding. Inflammation clears bacteria and debris — the redness and swelling of a fresh wound are this phase working, not failing. Proliferation builds new tissue: capillaries, collagen, and a fragile new surface. Remodelling then reorganises that collagen for a year or more, which is why a scar keeps changing long after the skin looks closed.
Acute versus chronic
An acute wound follows a predictable timetable: a surgical incision or a clean cut is sealed in days and strong within weeks. A chronic wound has lost that timetable. By convention, a wound that has shown no measurable healing after four to six weeks is called chronic. It is not simply a slow acute wound; its cells behave differently, its surface is often covered by a stubborn biofilm, and its healing signals are out of balance.
Healing is measured in months, not weeks
A chronic wound that closes over three to six months of consistent care is a success, not a failure. Progress is judged by measured area, depth, and tissue quality week by week — not by how the wound looks on any single day. Expecting a venous ulcer or a diabetic foot wound to close in a fortnight leads people to abandon treatment that was in fact working.
Why healing stalls
Four problems account for most wounds that will not heal. Pressure or shear repeatedly injures tissue that is trying to repair itself. Poor perfusion — from arterial disease, or from the swelling of venous disease — starves the wound of oxygen and nutrients. Infection and biofilm provoke persistent inflammation. And systemic disease, especially uncontrolled diabetes, impairs every phase of repair. Where several of these are present at once, none of them can be fixed in isolation.
What this means for treatment
Because the causes are mechanical, vascular, and metabolic as much as local, treatment is rarely a matter of finding a better dressing. Offloading, compression, assessment of the circulation, blood-sugar control, and debridement do the heavy lifting. Dressings protect the wound while those measures take effect; they do not substitute for them.
Seek urgent review if
- A wound is enlarging, deepening, or beginning to expose bone, tendon, or joint.
- There is spreading redness, fever, foul odour, or pus — infection may be deep rather than on the surface.
- A toe or foot turns black, cold, or blue, or you lose sensation in it.
Frequently asked questions
How long does a chronic wound take to close?
Months, not weeks. A wound that closes over three to six months of consistent care is a success rather than a failure. Progress is judged by measured area, depth and tissue quality week by week, not by how the wound looks on any single day.
What is the difference between an acute and a chronic wound?
An acute wound follows a predictable timetable and is usually sealed in days and strong within weeks. A chronic wound has lost that timetable; by convention, a wound showing no measurable healing after four to six weeks is called chronic.
Why does a wound stop healing?
Four problems account for most stalled wounds: repeated pressure or shear, poor perfusion from arterial or venous disease, infection and biofilm, and systemic disease such as uncontrolled diabetes. Where several are present at once, none can be corrected in isolation.
Risks & Limitations
- Chronic wounds heal over months, not weeks. A wound that closes in three to six months of consistent care is a good result.
- Recurrence is common. Both diabetic foot wounds and venous leg ulcers frequently return, which is why protective footwear and compression continue after healing.
- Partial or complete failure of a skin graft or flap, which may require further surgery.
- Infection and biofilm, which delay healing by weeks and can spread deeply or into bone.
- Amputation risk in diabetes and vascular disease, which is reduced but never abolished by treatment.
- Prolonged dressings and repeated clinic visits. Offloading, compression, and follow-up are demanding and take months.
- Donor-site scarring and discomfort where a graft or flap was taken.
- Reduced or absent sensation in grafted and flap tissue, and around a healed diabetic foot wound.
When to Seek Care
- A wound that is enlarging or deepening, or that begins to expose bone, tendon, or joint.
- Black, grey, or dead tissue appearing in or around the wound.
- Spreading redness, warmth, or swelling around the wound.
- Fever, shivering, or feeling generally very unwell.
- Foul odour or pus from the wound.
- New or severe pain, including pain in the leg or foot at rest or at night.
- A toe or foot that turns black, cold, or blue.
- Loss of sensation in a foot or toe, or a new wound or blister you cannot feel.
References & Further Reading
- World Health Organization (WHO) — chronic wound and diabetes care resources
- NICE (National Institute for Health and Care Excellence) — guidance on wound care, diabetic foot problems, and pressure ulcers
- Wounds International — international consensus documents on wound infection, biofilm, and compression therapy
- American Society of Plastic Surgeons (ASPS) — plastic surgery guidance on wound closure
- Cochrane Library — systematic reviews in wound care and wound closure
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.