Proposed Update to the IDSA Classification of Skin and Soft Tissue Infections in Diabetes

Ben Lipsky, Warren Joseph and Michael Silverman propose a provocative but logical update to the Infectious Diseases Society (IDSA) classification system. What’s even more terrific and inspiring is that it’s based on the failure of a large, well-controlled study of topical antibiotics for mild infections.

 

 

Update:

Table 1.

Concordance of IDSA Classification Schemes for Severity of SSTIs (COCLASSTI) and Infected DFUs (Adapted From 3 and 4)a

Skin and Soft Tissue Infections Infected Diabetic Foot Ulcers
Category Clinical Features Current Management IDSA Infection Severity Clinical Features Current Management Amenable to Topical Therapy?
Class 1 Superficial skin infections
• Impetigo
• Ecthyma
• Superficial, limited wound infections
Drainage (if required) and oral antibiotics in the outpatient setting. Occasionally topical antibiotics Mild Local infection involving only the skin and the subcutaneous tissue (without involvement of deeper tissues and without systemic signs as described below). If erythema, must be >0.5 cm to ≤2 cm around the ulcer. Exclude other causes of an inflammatory response of the skin (eg, trauma, gout, fracture). Usually treated with oral antibiotics in the outpatient setting Yes
Class 2A Systemically well
Erysipelas & cellulitis
Purulent skin and soft infections
• Abscess
• Furuncle, carbuncle
Traumatic wounds
• Surgical site infections
• Animal bites
• Other trauma (eg, pressure, thermal, pun
cture, crush)
Oral or intravenous (often outpatient) antibiotic therapy; may require short period of hospital observation Moderate – Class A Local infection (as described above), but with erythema extending >2 cm from rim of ulcer May be treated with oral, or initial parenteral with rapid switch to oral, antibiotics Potentially, but as adjunctive to systemic antibiotic therapy
Class 2B Systemically unwell, but no systemic inflammatory response syndrome (SIRS)
Erysipelas & cellulitis
Purulent skin and soft infections
• Abscess
• Furuncle carbuncle
Traumatic wounds
• Surgical site infections
• Animal bites
Other trauma (eg, pressure, thermal, puncture, crush)
Oral or outpatient parenteral antibiotic therapy; may require short period of hospital observation Moderate – Class B Local infection (as described above) involving structures deeper than skin and subcutaneous tissues (eg, abscess, osteomyelitis, septic arthritis, fasciitis), but with no evidence of systemic inflammatory response syndrome (as described below) May be treated with oral or initial parenteral antibiotics No
Class 3 Sepsis syndrome and life-threatening infection
Necrotizing infections of skin and soft tissues
• Necrotizing fasciitis
• Gas gangrene
• Pyomyositis
Likely to require admission to intensive care unit, urgent surgical assessment, and treatment with parenteral antibiotics Severe Local infection (as described above) with evidence of SIRS, as manifested by ≥2 of the following:
• Temperature >38°C or <36°C
• Heart rate >90 beats/ min
• Respiratory rate >20 breaths/min or PaCO2 <32 mm Hg
• White blood cell count >12 000 or <4000 cells/μL or ≥10% immature (band) forms
Treat, at least initially with parenteral antibiotic(s) No

Abbreviations: DFU, diabetic foot ulcer; IDSA, Infectious Disease Society of America; SIRS, systemic inflammatory response syndrome.

aNote that in the original publications, the rows in boldface type are not separated into “A” and “B”, as shown here. Infection defined as presence of at least 2 of the following items: (1) local swelling or induration; (2) erythema; (3) local tenderness or pain; (4) local warmth; (5) purulent discharge (thick, opaque to white or sanguineous secretion).

Source: Proposed New Classification of Skin and Soft Tissue Infections Modeled on the Subset of Diabetic Foot Infection | Open Forum Infectious Diseases | Oxford Academic

David G. Armstrong

Dedicated to amputation prevention, wound healing, diabetic foot, biotechnology and the intersection between medical devices and consumer electronics.

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