Symptoms and Diagnosis

  • Diagnosis of skin and soft tissue infections (SSTIs) is based primarily on clinical examination.1
  • Microbiological investigation recommended where possible in purulent infections. Etiology is confirmed in over 60% of these cases.2
  • Radiological examination and laboratory tests can also aid diagnosis of the severity of acute bacterial skin and skin structure infections (ABSSSI) including the need for hospitalization.1,3
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Symptoms and diagnosis

Overview of Characteristics of Acute Bacterial Skin and Skin Structure Infections (ABSSSI)

Patients with ABSSSIs present with erythema, warmth, edema, and pain over the affected site.1 Systemic features of infection may follow, their intensity reflecting the severity of infection. Common pathogens include Streptococcus pyogenes, Staphylococcus aureus and other Gram-positive bacteria.1,2,4

Characteristics of ABSSSIs

General Principles of Diagnosing SSTI

Comprehensive diagnosis of SSTIs often starts with a clinical history and findings from physical examination that help assess the severity of an infection. Although diagnosis of SSTIs is based on clinical presentation, microbiologic investigation is recommended in certain situations; for example, routine Gram-stain and culture of purulent material from carbuncles and abscesses are recommended by the Infectious Disease Society of America (IDSA).11 A precise diagnosis guides the decision on prompt and appropriate treatment.3,11

 

Radiological examination and imaging aid investigations of deep tissue infections to assess site and size of infection and any vascular involvement which can guide surgical drainage procedures.1,3 For patients with severe infection or comorbid conditions, common laboratory investigations can include complete blood count, C-reactive protein level, and liver and kidney function tests.1,3

 

Diagnosis of SSTIs relies primarily on clinical examination and findings, although microbiological investigation confirms the cause in over 60% of cases, suggesting a predominance of Gram-positive bacteria.2 The approach to diagnosis should follow the principles set out in guidelines from the Infectious Diseases Society of America (IDSA) on SSTIs, which involves assessment of severity, and recommends management approaches based on whether infections are purulent or non-purulent.

Considerations for Diagnosis of SSTIs1,3

Determining the Severity of SSTI

The IDSA guidelines on SSTI define mild, moderate and severe disease based on the presence of systemic signs and symptoms of infection and other patient specific variables.11

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References

  1. Ramakrishnan K, Salinas RC, Agudelo Higuita NI. Skin and Soft Tissue Infections. Am Fam Physician. 2015;92(6):474–483.
  2. Pulido-Cejudo A, Guzmán-Gutierrez M, Jalife-Montaño A, et al. Management of acute bacterial skin and skin structure infections with a focus on patients at high risk of treatment failure. Ther Adv Infect Dis. 2017;4(5):143–161.
  3. Leong HN, Kurup A, Tan MY, et al. Management of complicated skin and soft tissue infections with a special focus on the role of newer antibiotics. Infect Drug Resist. 2018;11:1959–1974.
  4. Dryden MS. Complicated skin and soft tissue infection. J Antimicrob Chemother. 2010;65 (Suppl 3):iii35–44.
  5. Esposito S, Bassetti M, Concia E, et al. Diagnosis and management of skin and soft-tissue infections (SSTI). A literature review and consensus statement: an update. J Chemother. 2017;29(4):197–214.
  6. Tognetti L, Martinelli C, Berti S, et al. Bacterial skin and soft tissue infections: review of the epidemiology, microbiology, aetiopathogenesis and treatment: a collaboration between dermatologists and infectivologists. J Eur Acad Dermatol Venereol. 2012;26(8):931–941.
  7. FDA. Guidance for Industry Acute Bacterial Skin and Skin Structure Infections: Developing Drugs for Treatment. Available from: https://www.fda.gov/media/71052/download  (accessed October 15 2020).
  8. Dalal A, Eskin-Schwartz M, Mimouni D, et al. Interventions for the prevention of recurrent erysipelas and cellulitis. Cochrane Database Syst Rev. 2017;6(6):Cd009758.
  9. Sibbald RG, Orsted H, Schultz GS, et al. Preparing the wound bed 2003: focus on infection and inflammation. Ostomy Wound Manage. 2003;49(11):24–51.
  10. Esposito S, Noviello S, Leone S. Epidemiology and microbiology of skin and soft tissue infections. Curr Opin Infect Dis. 2016;29(2):109–115.
  11. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):147–159