Chronic Wounds
Section editor:
Chronic wounds are injuries that fail to heal in a normal, timely way. Chronic wounds may stall (e.g. due to prolonged inflammation) or deteriorate (e.g. due to infection). Common chronic wounds include pressure injuries, venous ulcers, arterial ulcers and diabetic ulcers. Chronic wounds create a substantial clinical and economic burden worldwide. Understanding the basic physiology of wound healing and how it goes awry in chronic wounds is essential for all clinicians who manage them.
Key Takeaways
- Chronic wounds fail to progress through normal healing stages and often remain in a prolonged inflammatory state.
- They represent a significant human and healthcare burden, affecting millions and costing billions annually.
- Normal wound healing is a coordinated, multi-stage process, and disruption at any point can lead to chronicity.
What Are Chronic Wounds?
Chronic wounds are wounds that do not follow the usual orderly and timely process of healing and remain open far beyond expected timeframes. Although there is varying discussion on exact timeframes (4 weeks versus 3 months), they are frequently defined clinically as wounds that have not healed after a specific expected period of time.1,2
In contrast to acute wounds (which usually close and heal predictably), chronic wounds may remain “stalled” or fail to regain normal tissue integrity because of underlying local or systemic problems that prevent progression through the normal healing stages.2
Why Chronic Wounds Matter
Chronic wounds are far more than delayed injuries; they have major impacts on patients, families, caregivers and health systems:3
- Prevalence and healthcare burden: In the United States alone, chronic wounds affect millions of people, particularly older adults, and cost Medicare billions each year.
- Quality of life: Wounds that don’t heal can cause pain, limit mobility, lead to infections, and negatively affect body image and psychological and social well-being.
- Healthcare costs: Globally, chronic wound care is a sprawling economic burden, with total expenditures in the tens of billions of dollars.
Because chronic wounds are associated with significant morbidity and healthcare use, understanding the underlying biology is an important foundation for improving care.
Normal Wound Healing: A Quick Overview
Wound healing is a highly coordinated physiological process involving multiple cell types, chemical signals, and structural tissue changes.4,5
Stages of Healing
Although sources vary in their phase definitions, standard descriptions include four overlapping stages:4
- Hemostasis: Immediately after injury, blood vessels constrict and clotting begins to stop bleeding.
- Inflammation: White blood cells clear microbes and debris.
- Proliferation: New tissue begins to form, including granulation tissue, new blood vessels (angiogenesis), and early formation of dermal matrix.
- Remodeling: Collagen reorganizes and tissue strengthens over weeks to months.
The successful transition through each stage depends on a regulated interplay of cells, growth factors, and extracellular matrix components.
What Happens in Chronic Wounds?
In chronic wounds, the normal healing sequence is disrupted. Rather than progressing through healing stages, chronic wounds frequently remain in a prolonged or exaggerated inflammatory phase, characterized by persistent inflammation and an inability to advance to tissue formation and remodeling.4 Many factors can contribute to wound chronicity, including biofilms, infection, pressure, poor circulation, comorbid conditions, and more. Chronic wounds are most prevalent in people over 75.5
Importantly, chronic wounds are not just “slow healers”—they represent a failure of the body’s repair mechanisms due to complex interactions between systemic health, local tissue conditions, and cellular signaling.
Conclusion
Understanding chronic wounds begins with understanding the physiology of normal healing and recognizing how this process can be derailed. Chronic wounds represent a significant health challenge due to their high prevalence, patient impact, and cost to healthcare systems. A solid grasp of the basic definitions and biology of wound healing lays the groundwork for more advanced discussions of assessment and management.
References
- Bowers S, Franco E. Chronic wounds: evaluation and management. Am Fam Physician. 2020;101(3):159-166.
- Labib A, Winters R. Complex wound management. In: StatPearls [Internet]. StatPearls Publishing; 2025. Accessed January 28, 2026. https://www.ncbi.nlm.nih.gov/books/
- Sen CK. Human wound and its burden: updated 2025 compendium of estimates. Adv Wound Care (New Rochelle). 2025;14(9):429-438. doi: 10.1177/21621918251359554. Epub 2025 Jul 14.
- Ozgok Kangal MK, Kopitnik NL. Physiology, wound healing. In: StatPearls [Internet]. StatPearls Publishing; 2025. Accessed January 28, 2026. https://www.ncbi.nlm.nih.gov/books/NBK535406/
- Shah JB, Milne CT. Wound Care Certification Study Guide. Best Publishing Company, North Palm Beach, Florida, 2021.
