EBQ:TMP-SMX vs Placebo for Uncomplicated Skin Abscess

The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Complete Journal Club Article
Talan DA et al.. "Trimethoprim–Sulfamethoxazole versus Placebo for Uncomplicated Skin Abscess". NEJM. 2016. 374(9):823-832.
PubMed Full text PDF

Clinical Question

In settings with MRSA, does Trimethoprim-sulfamethoxazole treatment after Incision and drainage of an abscess result in a greater cure rate?

Conclusion

Trimethoprim–sulfamethoxazole treatment resulted in a higher cure rate among patients with a drained cutaneous abscess than placebo for abscess that are successfully drained.

Major Points

Methicillin-resistant Staphylococcus aureus (MRSA) is a well known cause of many abscesses in the ED being the most common cause of purulent skin and soft-tissue infections.[1][2][3] Treatment for cutaneous abscesses has been incision and drainage with antibiotics generally reserved for those that also had associated cellulitis. This multicenter, double-blind, randomized Controlled Trial of 5 US EDs with >1200 patients challenges the traditional dogma of no antibiotics for simple small uncomplicated abscesses that can be drained. For abscess of median size, 2.5 x 2.0 x 1.5cm that underwent I&D and co-administration of 5 days of TMP/SMX, cure rates were 80.5% vs 73.6% with placebo and I&D.[4]

Study Design

  • Multi-Center, Double-Blind RCT
  • ED based; sites in Los Angeles, Phoenix, Philadelphia, Baltimore, Kansas City

Population

Patient Demographics

  • Age: 35yo
  • Male: 58%
  • Days with skin symptoms: 4
  • MRSA History: 7%
  • Diabetes: 11%
  • Abscess Location:
    • Head/Neck: 81-89%
    • Trunk/Abdomen: 20%
    • Groin/buttock: 20%
    • Arms/hands: 23%
    • Legs/feet: 21%
  • Abscess size: 2.5 X 2.0 X 1.5 cm

Inclusion Criteria

  • Age >12 years of age
  • Cutaneous lesion that was:
    • Either suspected to be an abscess on the basis of physical examination or
    • Confirmed via ultrasonography AND
    • Found to have purulent material on after I&D proration
  • Abscess for less than 1 week
  • Size of at least 2.0 cm in diameter (measured from boarder to border)
  • Deemed to be eligible for outpatient treatment per the ED physician

Exclusion Criteria

  • Suspected osteomyelitis or septic arthritis
  • Diabetic foot, decubitus, or ischemic ulcer
  • Mammalian bite
  • IVDU
  • Long-term care residence
  • Incarceration
  • Immunodeficiency (i.e. ANC <500/mm3)
  • Immunosuppressive drugs
  • Active chemotherapy
  • Known AIDS
  • Creatinine clearance <50mL/min
  • Taking warfarin, phenytoin, or methotrexate
  • Pregnant or lactating

Interventions

  • Intervention Group: 7 days TMP/SMX single strength (80mg TMP-400mg SMX) 4 tabs twice daily
  • Control Group: Placebo

Outcomes

Primary Outcome

'Clinical cure of the abscess lesion at 'test of cure' visit 7-14 days after the end of the treatment period

  • Intention to treat analysis (p=0.005):
    • TMP/SMX Group: 80.5%
    • Placebo Group: 73.6%
  • Per Protocol analysis (p<.001):
    • TMP/SMX Group: 92.9%
    • Placebo Group: 85.7%

Secondary Outcomes

  • New skin infection at different site:
    • TMP/SMX group: 3.1%
    • Placebo group: 10.3%
  • Recurrent skin infection at abscess site:
    • TMP/SMX group: 2.1%
    • Placebo group: 3.0%

Subgroup analysis

Criticisms & Further Discussion

  • The results of this study are only generalizable to the study population where most abscesses measured between 2 – 3 cm. There were however abscess >5cm with surrounding cellulitis where antibiotics are traditionally perscribed
  • The number needed to treat to cure an abscess is 14 for TMP/SMX use
  • Only 64.7% of the treatment group was 100% adherent with 17.2% being 76 – 99% adherent which make the results especially applicable to the ED population and giving a good estimate of actual patient adherence.
  • Although TMP/SMX is not without side effect, no evidence of SJS was found in the study population.
  • The cure rate was > 80% in the placebo group demonstrating the importance of adequate I&D
  • Prior evidence, although possibly underpowered, had not found a statistical difference in cure rates but did confirm the finding of reduced formation of subsequent lesions.[5]

External Links

See Also

Funding

Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT00729937

References

  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. [EBQ:TMP-SMX vs Placebo for Uncomplicated Skin Abscess|Bactrim and I&D NEJM]]
  5. Schmitz GR et al. Randomized controlled trial of trimethoprim-sulfamethoxazole for uncomplicated skin abscesses in patients at risk for community-associated methicillin-resistant Staphylococcus aureus infection. Ann Emerg Med. 2010 Sep;56(3):283-7.