• MRSA is the most common cause of purulent skin and soft-tissue infections.[1][2][3]

Clinical Features

  • Tender nodular region with surrounding induration
  • Fluctuance
  • Surrounding erythema

Differential Diagnosis

  • Cyst
  • Vascular malformation

Skin and Soft Tissue Infection



Fluctulance on exam
Abscess on ultrasound
  • Clinical exam: fluctulance +/- erythema
  • Soft tissue ultrasound can differentiate between abscess and cellulitis
    • Assess for fluid collection and swirl within the collection


  • Incision and drainage
  • Packing
    • Abscess >5 cm in diameter
    • Pilonidal abscess
    • Abscess in an immunocompromised or diabetic patient
  • Antibiotics
    • Although withholding antibiotics is part of Choosing wisely ACEP, new evidence suggest antibiotic NNT of 14 to prevent 1 treatment failure[4]
    • TMP/SMX DS BID x 5 days (all abscesses)[5]
    • Consider more aggressive antibiotic treatment if concomitant cellulitis



  • Reserved for significantly ill patients or those requiring surgical intervention


  • Appropriate for majority of patients
    • Follow up in 2 days for wound check

See Also

External Links


  1. Maligner D et al. The prevalence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) in skin abscesses presenting to the pediatric emergency department. N C Med J. 2008 Sep-Oct;69(5):351-4.
  2. Pickett A et al. Changing incidence of methicillin-resistant staphylococcus aureus skin abscesses in a pediatric emergency department. Pediatr Emerg Care. 2009 Dec;25(12):831-4.
  3. Bradley W. Frazee et al. High Prevalence of Methicillin-Resistant Staphylococcus aureus in Emergency Department Skin and Soft Tissue Infections http://dx.doi.org/10.1016/j.annemergmed.2004.10.011
  4. Talan DA, et al. Trimethoprim–Sulfamethoxazole versus placebo for uncomplicated skin abscess. NEJM. 2016; 374(9):823-832.
  5. EBQ:TMP-SMX vs Placebo for Uncomplicated Skin Abscess