Globally, skin, and soft-tissue infections (SSTIs) are frequent reasons for medical visits in both inpatient and outpatient settings. SSTIs include a number of conditions ranging from simple superficial infections to complicated surgical wound infections and rare, but rapidly progressing necrotising fasciitis. The latter is often referred to as ‘flesh-eating disease’, although the bacteria that cause it do not ‘eat’ flesh, but release toxins that damage nearby tissue. The most common types are SSTIs are cellulitis and abscesses.2,4
A subset of severe SSTIs, known as complicated SSTIs (cSSTIs) require early prompt treatment that generally includes both surgery with drainage and debridement, as well as appropriate antibiotic therapy.2
cSSTIs are further classified as necrotising or non-necrotising. Common cSSTIs include:2
- Surgical site infections
- Traumatic wound infections
- Diabetic foot infections
- Perianal abscesses
- Extensive cellulitis (typically presents as a poorly demarcated, warm, erythematous area with associated oedema and tenderness to palpation. If left untreated, it can gangrene)5
- Infections occurring in patients with significant comorbidities that affect the therapeutic response.
Skin wound repair is a complex physiological process, comprising several different stages:1
Stage 1 (haemostasis): blood leaks out of the body. The first step of haemostasis is when blood vessels constrict to restrict the blood flow. Next, platelets stick together in order to seal the break in the wall of the blood vessel. Finally, coagulation occurs and reinforces the platelet plug with threads of fibrin which are like a molecular binding agent. The haemostasis stage of wound healing happens very quickly.
Stage 2 (inflammatory): inflammation lasting from 24 hour to four to six days. This stage begins with the release of proteolytic enzymes and proinflammatory cytokines from invasive immune cells into the wound area, and these inflammatory cells produce reactive oxygen species (ROS) to protect the organism from bacterial infection. At this stage, all foreign bodies and tissue debris are removed from the wound bed by neutrophils and macrophages, thus preventing infection. Furthermore, the release of cytokines and enzymes stimulate the growth of fibroblasts and myofibroblasts, and wound exudate ensures the necessary moisture for healing.
Stage 3 (proliferation): new granulation tissue forms and grows in the wound area to form the new extracellular matrix.
Stage 4 (remodelling): the matrix composition changes and collagen III is replaced by collagen I, which leads to the increased tensile strength of new tissues (remodelling).
Wounds that have not progressed through the normal process of healing and are open for more than a month are classified as chronic wounds. Older patients (>65-years), those who have diabetes, as well as people living with obesity are at high risk of developing chronic wounds.3
Managing chronic wounds
Self-healing of wound is slow and susceptible to external infections, hence appropriate wound dressing is needed to promote and guide the healing process. Optimal dressings are defined as being able to maintain
high humidity at the wound site, remove excess exudates, have non-toxicity and non-allergy reaction, allow oxygen exchange, prevent microbial invasion, be comfortable, and cost-effective.1
In 2021, a group of international experts published a guideline on wound bed preparation. The overarching aim of wound bed preparation is to optimise chronic wound treatment. Below is a short summary:5
Statement #1: Optimal, timely diagnosis and treatment of the wound cause are the most important aspects of chronic wound care
Clinicians must identify the wound cause as precisely as possible, considering vascular leg ulcers (venous, mixed, arterial, lymphatic, or combinations), diabetic foot ulcers (neuropathic, ischaemic, or mixed), and pressure injuries (which must be distinguished from moisture-associated skin damage) because each has specific management considerations. Other diagnoses include inflammatory ulcers (pyoderma gangrenosum, vasculitis), malignant ulcers (primary skin, other secondary malignancies), trauma/previous surgeries, medications, and congenital or acquired coexisting diseases.
Statement #2: Diagnosing and managing pain
There are two major types of pain: nociceptive and neuropathic. Nociceptive pain relates to the injury, is stimulus dependent and is typically associated with aching, gnawing, tender, or throbbing sensations. Neuropathic pain is often spontaneous and described as burning, shooting, stinging, or stabbing. Each type has a different physiologic basis, necessitating different pharmacologic treatment.
Statement #3: Determine ability to heal
One of the first things clinicians must do after diagnosing the wound is to determine healability. Generally, chronic wounds fall into one of three categories: healable, maintenance, and nonhealable. Timely intervention by skilled healthcare providers, and an interdisciplinary team are required to determine healability (see box 1).
Statement #4: Monitor wound history and clinical examination
Document wound(s): location, longest length × widest width at right angles, wound shape, wound bed, exudate, margin, undermining, tunneling, surrounding skin condition, and photoimaging when available.
Statement #5: When appropriate, debride wounds with adequate pain control
Debridement is a way to remove slough, debris, or foreign substances that may facilitate infection or act as a proinflammatory stimulus, prolonging the inflammatory stage of wound healing and delaying the proliferative reparative process. Sharp surgical debridement requires assessment of the blood supply to be sure it is adequate for healing. Before starting, providers who are considering even conservative debridement methods must ensure they have appropriate competency, scope of practice, the required equipment, and support in the event of bleeding, as well as alignment with their facility’s policies and procedures.
Statement #6: Assess and treat wounds for infection/inflammation
Wound infections have two compartments: one superficial and the other deep. Wounds can be thought of as a bowl of soup: the thin layer on the surface of a wound is analogous to the superficial compartment, and the sides and bottom of the soup bowl are equivalent to the surrounding and deep components of a chronic wound. Treat local infection (three or more NERDS* criteria) with topical antimicrobials (silver, iodine, polyhexamethylenebiguanide [PHMB]/chlorhexidine, methylene blue/crystal violet, surfactants). Consider treating deep and surrounding infection (three or more STONEES** criteria) with systemic antimicrobials. Evaluate and alleviate persistent inflammation including consideration of anti-inflammatory agents (topical dressings, systemic medication).
Statement #7: Moisture management
Providers must select an appropriate dressing to match the wound characteristics and individual patient needs. Ideal moisture management depends on a wound’s healability.
Statement #8: Evaluate the rate of healing
If a wound is not at least 20% to 40% smaller by week four, it is unlikely to heal by week 12. Stalled (healable) wounds should be re-evaluated for alternate diagnoses; consider wound biopsy, further investigation, and/or referral to an interprofessional assessment team to optimise treatment (see box 1).
Statement #9: Edge effect
Use active therapies for stalled but healable wounds. These therapies include eg negative-pressure wound therapy, electrical stimulation, cellular and/or tissue-based products, skin grafts, ultrasound, and hyperbaric oxygen therapy. Some of these therapies have better evidence for acute wounds than with chronic, nonhealing wounds (eg, negative-pressure wound therapy after diabetic foot surgery, split-thickness skin grafts), particularly where the cause is not or cannot be corrected. If an active therapy is selected, it is imperative that a consistent and accurate wound assessment be conducted so that wound progression in either direction may be determined and the therapy discontinued in a timely manner if the wound is not on a healing trajectory.
Statement #10: Organisational plan
Elements of an effective organisational plan for guideline implementation are as follows:
- Assess organisational readiness and barriers to implementation, considering local circumstances
- Involve all members (whether in a direct or indirect supportive function) in the implementation process
- Provide ongoing educational opportunities to reinforce best practice.
- One or more qualified individual(s) should provide the support needed for the education and implementation process
- Provide opportunities for reflection on personal and organisational experience in implementing guidelines.
Box 1: Pathway for the management of non-healable and maintenance wounds
A group of South African wound care experts developed a pathway for the management of non-healable and maintenance wounds, which was also published last year. In summary they recommend:6
- Healability should be determined within the first 12 weeks using valid assessment tools. A systematic and comprehensive approach to history taking, physical examination, and laboratory investigations to reach a clear diagnosis improves outcomes. Lack of adequate blood supply remains a major underlying cause present in most nonhealing or maintenance wounds and should be assessed regularly
- If wound assessment reveals a maintenance or nonhealable wound, it is important to realise that this diagnosis will impact the patient on physical, personal, interpersonal, social, and financial levels. The main priority should be to preserve patient integrity in these arenas with a focused patient-centered intervention
- Management of nonhealable wound requires a multidisciplinary approach
- Long-term pain management should be prioritised. Furthermore, patient preparation with focused health dialogue is vital to identify and facilitate life adaptations needed to cope with this diagnosis
- The incorporation of newly learned or adapted skills into the patient’s own activities of daily living will positively impact quality of life
- Patients with maintenance, nonhealing, and hard-to-heal wounds should take responsibility for their own self-care where possible and for as long as possible.
NERDS stands for:
- Nonhealing: Wounds that are not 20% to 40% smaller in four weeks according to patient history or existing documentation
- Exudate: more than 50% of the dressing stained with exudate
- Red and bleeding: wound bed tissue is bright red with exuberant granulation tissue and tissue bleeds easily with gentle manipulation
- Debris: presence of discoloured granulation tissue, slough, and necrotic/nonviable tissue
- Smell: unpleasant or sweet, sickening odour
STONEES stands for:
- Size is bigger: Size as measured by the longest length and the widest width at right angles to the longest length, depth measured with a probe straight in
- Temperature ↑: increased periwound margin temperature by more than 3ºF difference between two mirror-image sites
- Os (probes, exposed): wounds that have exposed bone or that probed to bone at the time of examination have risk of osteomyelitis
- New areas of breakdown or satellite lesions
- Erythema and exudate: reddened skin in periwound area, presence of swelling in periwound area or increased amount of drainage
- Smell: unpleasant or sweet, sickening odour.
- Zheng L, Li S, Luo J and Wang X. Latest Advances on Bacterial Cellulose-Based Antibacterial Materials as Wound Dressings. Front Bioeng Biotechnol, 2020.
- Eckmann C and Tulkes PM. Current and future options for treating complicated skin and soft tissue infections: focus on fluoroquinolones and long-acting lipoglycopeptide antibiotics. Journal of Antimicrobial Chemotherapy, 2021.
- Sen CK. Human Wound and Its Burden: Updated 2020 Compendium of Estimates. Advances in Wound Care, 2021.
- Necrotising fasciitis. https://www.nhs.uk/conditions/necrotising-fasciitis/#:~:text=Necrotising%20fasciitis%20is%20a%20rare,toxins%20that%20damage%20nearby%20tissue.
- Brown BD, Hood Watson KL. [Updated 2021 Dec 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549770/
- Sibbald RG, Elliott JA, Persaud-Jaimangal R, et al. Wound Bed Preparation 2021, Advances in Skin & Wound Care: April 2021 - Volume 34 - Issue 4 - p 183-195 doi: 10.1097/01.ASW.0000733724.87630.d
- Boersema GC, Smart HRN, Hiske RN, et al. Management of Nonhealable and Maintenance Wounds: A Systematic Integrative Review and Referral Pathway, Advances in Skin & Wound Care: January 2021 - Volume 34 - Issue 1 - p 11-22 doi: 10.1097/01.ASW.0000722740.93179.9f
- Signs, Symptoms and Actions for Superficial and Spreading Wound Infection Oct 20, 2014. https://wwwoundcare.ca/Uploads/ContentDocuments/Signs%2C%20Symptoms%20and%20Actions%20for%20Superficial%20and%20Spreading%20Wound%20Infection%20%28All%20Etiology%27s%29%2C%20Care%20Partners%2C%20Oct%2020%2C%202014.pdf