Chronic wounds

Chronic wounds are wounds that do not begin to heal within 4 weeks despite appropriate care. They are caused by cessation or disruption of one of the phases of wound healing, typically the inflammation phase. Chronic wounds most commonly occur in older adults and individuals with diabetes, peripheral arterial disease, chronic venous insufficiency, prolonged immobilization, or malnutrition. Diagnosis involves assessing for underlying risk factors and complications such as infection, as well as biopsy in selected cases. Management is multifactorial and includes treatment of the underlying cause (e.g., diabetes) and meticulous local wound care with regular debridement, maintenance of appropriate moisture balance, and infection control.

This article provides an overview of chronic wounds; see “Chronic venous disease,” “Peripheral arterial disease,” “Diabetic foot ulcers,” and “Decubitus ulcers” for more detailed information on specific wound types.

• Chronic wounds develop due to cessation or disruption of one of the phases of wound healing (most commonly the resorptive, or inflammation, phase).
• Most commonly occurs in patients with multiple risk factors for delayed wound healing
• The proliferative wound healing phase is delayed in individuals with copper and vitamin C deficiency.
• Zinc deficiency can delay wound healing because the collagenases responsible for collagen remodeling require zinc for proper function.

All chronic wounds begin as acute wounds.

There are multiple risk factors for delayed wound healing, including: ^[1][3]

• Systemic factors
  • Chronic systemic diseases (e.g., diabetes mellitus, chronic liver disease, chronic kidney disease, connective tissue disease)
  • Malnutrition (e.g., deficiency of zinc, copper, vitamin C; hypoproteinemia) ^[1][4]
  • Medications (e.g., steroids, cytotoxics, and other immunosuppressants including bevacizumab) ^[5]
  • High cortisol levels ^[6]
  • Hypothermia ^[7]
  • Phagocyte immunodeficiencies (e.g., leukocyte adhesion deficiency type 1) ^[8]
• Regional factors
  • Infection
  • Insufficient arterial supply (e.g., peripheral vascular disease)
  • Insufficient venous drainage (e.g., chronic venous disease)
  • Lymphedema
  • Peripheral neuropathy
  • Sustained pressure (decubitus ulcers)
  • Excessive tension on the wound edges ^[9]
  • Repeated local trauma
  • History of radiation therapy to the site
  • Presence of a foreign body (e.g., orthopedic hardware) ^[1]
• Other factors
  • Older age
  • Use of tobacco products ^[10]
  • Social determinants of health including barriers to accessing health care ^[11]

• No progression towards healing within 4 weeks of appropriate care
• Frequently located in poorly vascularized areas or areas of high pressure ^[2]
• Wound bed may have granulation tissue, slough, or eschar. ^[12]
• Signs of localized chronic wound infection ^[13]
  • Localized erythema, warmth, and edema
  • Friable granulation tissue
  • Increased exudate or purulent discharge, odor, and/or pain
  • Delayed healing
• Signs of spreading chronic wound infection ^[13]
  • Cellulitis of surrounding skin (erythema > 2 cm from wound edge)
  • Extending induration
  • Lymphangitis
  • Crepitus
  • Wound dehiscence
  • Systemic signs (e.g., fever and malaise)
• Features of the underlying cause may be present, e.g.: ^[1][2]
  • Clinical features of peripheral arterial disease
  • Clinical features of chronic venous insufficiency
  • Clinical features of peripheral neuropathy

The diagnostics for specific types of chronic wounds are detailed in the relevant articles (e.g., “Chronic venous disease,” “Peripheral arterial disease,” “Diabetic foot ulcers,” “Decubitus ulcers”).

• Perform a clinical evaluation of all wounds, e.g., for:
  • Size, location, and depth
  • Presence of drainage and/or odor
  • Tissue type (e.g., granulation tissue, slough, necrotic tissue)
• Assess for underlying risk factors for delayed wound healing. ^[1][2]
  • Consider obtaining diagnostics for malnutrition in adults. ^[3]
  • Lower extremity wounds: Perform a vascular evaluation, including lower extremity pulses and ABI.
  • Obtain additional targeted diagnostics as needed (e.g., diagnostics for chronic venous insufficiency, diagnostics for diabetes mellitus).
• Obtain diagnostics for infection based on clinical evaluation. ^[1][13]
  • Indications
    • All patients: signs of spreading chronic wound infection
    • Immunocompromised patients: Consider diagnostics if there are signs of localized chronic wound infection.
  • Methods
    • Obtain punch biopsy (preferred) or superficial swab using the Levine technique. ^[1]
    • Send molecular analysis (preferred, if available) or wound culture. ^[1]
• Positive probe-to-bone test: Obtain diagnostics for osteomyelitis.
• Consider biopsy and histopathology for: ^[2]
  • Atypical wounds or wounds of unclear etiology
  • Suspected carcinoma (e.g., Marjolin ulcer)

Document the initial evaluation of the wound (e.g., location, size, depth, tissue type, presence of drainage) to establish a baseline for monitoring over time. ^[2]

Swab cultures obtain superficial specimens and may not be able to detect bacteria in deeper tissues or biofilm-associated bacteria, which commonly colonize chronic wounds. ^[14]

The following is a general overview for chronic wounds; for type-specific management, see the relevant articles (e.g., “Chronic venous disease,” “Peripheral arterial disease,” “Diabetic foot ulcers,” “Decubitus ulcers”).

Approach ^[1][2]

• Develop a wound management plan in conjunction with a multidisciplinary team.
• Optimize management of modifiable risk factors for delayed wound healing (e.g., treatment of diabetes, treatment of peripheral arterial disease).
• Ensure adequate pain management (see “Chronic noncancer pain management”).
• Educate patients on wound self-care.
• Reduce stress on the wound.
  • Immobilize wounds that are around joints (e.g., with a splint or cast).
  • Offload areas of pressure.
• Regularly evaluate the wound for:
  • Serial wound debridement (except for arterial ulcers)
  • Management of wound edges
  • Dressing changes
  • Signs of infection
• After 4 weeks of initial treatment, evaluate healing.
  • ≥ 50% reduction in wound surface area: Continue current treatment regimen.
  • < 50% reduction in wound surface area: Re-evaluate treatment regimen and/or consider referral.
• Refer patients with large, complex, or refractory wounds to surgery or plastic surgery for consideration of advanced wound care (e.g., skin grafting or flaps).

Wound debridement ^[15][16][17]

• General principles
  • Debridement is the removal of all dead and devitalized tissue from the wound bed to promote healing.
  • Select the appropriate debridement technique based on the patient and wound characteristics.
  • Perform debridement early and continue it weekly during initial treatment. ^[1]
  • Multiple modalities may be required (e.g., initial surgical debridement followed by maintenance enzymatic debridement). ^[1]
• Selective debridement
  • Removal of nonviable tissue while preserving healthy tissue
  • Performed in an outpatient setting
  • Typically painless
  • Progress may be slower than with nonselective debridement.
• Nonselective debridement
  • Some viable tissue is also removed during debridement.
  • Typically requires anesthesia or sedation and trained personnel

Debridement is an essential aspect of managing chronic wounds and wounds with biofilm. ^[1]

Chronic wound dressing ^{[1][18][19][20]}

Dressing selection

Wound dressings should maintain a moist environment , allow gas exchange, absorb exudate, minimize the risk of contamination, and be nonallergenic and easy to apply.

• Select an appropriate dressing based on:
  • Wound characteristics
  • Cost
  • Patient factors (e.g., patient age, comorbidities, adhesive allergy)
• Ensure the dressing is a suitable size, e.g.:
  • Extends beyond the wound edges on all sides
  • Sufficient size to absorb exudate ^[1][19]
• Consider the need for layers or a composite dressing. ^[18]
  • Second dressings should be placed over hydrogels, foam, and alginate dressings. ^[19][20]
  • Tubular or crepe bandages to hold dressings in place
  • Compression garments in venous ulcerations, wounds in edematous areas, and lower limb wounds (unless arterial insufficiency is present) ^[1]

Dressings should keep the wound bed moist to promote faster healing and reduce scarring while keeping the surrounding skin dry to prevent maceration. ^[1][19][20]

Adhesive backings can cause contact dermatitis and damage fragile skin. ^[19]

Dressing changes

• Change dressings regularly based on: ^[20]
  • Wound characteristics (e.g., infected wounds or wounds with high exudate may need daily or twice-daily dressing changes)
  • Type of dressing (follow the manufacturer's instructions) ^[18][19][21]
  • Integrity of the surrounding skin
• Determine the appropriate technique. ^[13][22][23]
  • Assess for indications for sterile technique:
    • Large wounds
    • Deep wounds (e.g., wounds with sinus tracts, wounds that extend into bone or peritoneal and pleural cavities)
    • Complex dressing change
    • Immunocompromised patients
  • If no indications for sterile technique, use clean technique.

Infection management ^[13]

• Perform surgical debridement for all infected wounds.
• Signs of localized wound infection: topical antimicrobials for at least 2 weeks
  • Preferred: topical antiseptics such as iodine, silver, and honey (available as ointments, pastes, and/or medicated dressings)
  • Selected cases with expert guidance, ideally only if sensitivities are known: topical antibiotics ^[19]
• Signs of spreading wound infection: systemic antibiotics (for medications and dosages, see "Cellulitis" and "Osteomyelitis") PLUS topical antimicrobials

Treat all diabetic foot infections with systemic antibiotics. ^[24]