From the Guidelines
A complicated skin and soft tissue infection (SSTI) is characterized by several key factors, including deeper tissue involvement, significant comorbidities, systemic signs of illness, and specific anatomical locations, which distinguish it from uncomplicated infections. These factors may include involvement of deeper tissue layers beyond the dermis, such as fascia or muscle, or occurrence in patients with significant comorbidities that may impair response to standard treatment, as noted in the 2018 WSES/SIS-E consensus conference recommendations 1. Complicated SSTIs often present with systemic signs of illness, such as fever, tachycardia, or hypotension, and may demonstrate extensive tissue involvement with rapidly spreading erythema, induration, necrosis, bullae formation, or crepitus.
Some of the key factors that classify an SSTI as complicated include:
- Deeper tissue involvement, such as fascia or muscle
- Significant comorbidities, such as diabetes mellitus, peripheral vascular disease, or obesity
- Systemic signs of illness, such as fever, tachycardia, or hypotension
- Specific anatomical locations, such as the hand, perineum, or areas overlying major joints
- Presence of foreign bodies, surgical site infections, animal or human bites, and infections requiring surgical intervention for source control
According to the 2018 WSES/SIS-E consensus conference recommendations, treatment of complicated SSTIs typically requires broad-spectrum antibiotics initially, such as vancomycin plus piperacillin-tazobactam, or meropenem, surgical debridement in many cases, and close monitoring in a hospital setting 1. The complexity of SSTIs arises from both the nature of the infection itself and the host factors that influence treatment response and outcomes.
It is essential to note that the classification and management of SSTIs have evolved over time, with various guidelines and recommendations published by different organizations, such as the Infectious Diseases Society of America (IDSA) and the World Society of Emergency Surgery (WSES) 1. However, the most recent and highest-quality study, the 2018 WSES/SIS-E consensus conference recommendations, provides the most up-to-date guidance on the classification and management of complicated SSTIs 1.
From the FDA Drug Label
Patients with complicated deep soft tissue infections including wound infections and cellulitis (≥ 10 cm, requiring surgery/drainage or with complicated underlying disease), major abscesses, infected ulcers, and burns were enrolled in the studies
- Complicated skin and soft tissue infections are characterized by:
- Deep soft tissue infections
- Wound infections
- Cellulitis (≥ 10 cm)
- Requiring surgery/drainage
- Complicated underlying disease
- Major abscesses
- Infected ulcers
- Burns A skin and soft tissue infection is considered complicated if it meets any of these criteria 2.
From the Research
Characteristics of Complicated Skin and Soft Tissue Infections
- Involvement of deeper soft tissues 3
- Involvement of methicillin-resistant Staphylococcus aureus (MRSA) which increases hospitalization, health care costs, and overall mortality 3
- Presence of systemic signs of sepsis 4
- Requirement for surgical intervention 4
- Presence of complicating co-morbidities 4
- Accompanying neutropenia 4
- Accompanying ischaemia 4
- Tissue necrosis 4
- Burns and bites 4
Causative Pathogens
- Staphylococcus aureus is the most common cause of complicated skin and soft tissue infections (cSSTIs) [(5,4)]
- MRSA is a common cause of cSSTIs [(3,5,6,7)]
- Polymicrobial infection with Gram-positive and Gram-negative organisms and anaerobes may occur 4
Treatment
- Incision, drainage, surgical debridement, broad-spectrum antibiotic therapy, and supportive care 3
- Newer antibiotics such as linezolid, tigecycline, daptomycin, and vancomycin are effective in treating cSSTIs [(3,5,6,7)]
- Selection of antibiotics should be based on drug characteristics, effectiveness, safety, and treatment costs 3
- Local Antimicrobial Stewardship Program strategies can guide clinicians for early initiation of specific treatments 3