This document summarizes several studies on the use of antibiotics for abscess management. A 2016 RCT of over 1000 patients found that high-dose Bactrim led to higher cure rates of abscesses over 2cm compared to placebo, especially for those with MRSA, fevers, or immunosuppression. A 2017 RCT of under 800 patients found Bactrim and clindamycin had similar cure rates of abscesses under 5cm as placebo. However, antibiotics were associated with higher adverse gastrointestinal events. Overall, meta-analyses show antibiotics reduce treatment failures and new skin infections compared to incision and drainage alone, but with a risk of serious drug side effects.

1. POP THAT PIMPLE
ROLE OF ANTIBIOTICS IN ABSCESS
MANAGEMENT

2. • Systematic review 2007
• Studies from RCTs from 1977 and 1982.
• Cohort studies from 2000’s
• Conclusion
Cure rates similar between I+D with antibiotics and I+D
alone.

3. GUIDELINES
Australian
• eTG
I+D alone.
Flucloxacillin if cellulitis
and systemic
symptoms.
USA
• Clinical Practice Guidelines by the
Infectious Diseases Society of
America
I+D is primary treatment.
Antibiotics
>5cm
Cellulitis
Systemic symptoms
Immunosuppression

5. TALAN ET AL.
• 2016
• USA, Multicentre RCT, Double blind
• 1247 patients
• High dose Bactrim (320/1600mg) BD for 7 days versus
placebo.
• Abscesses > 2cm in size.
• Primary outcome was clinical cure at 7-14 days.
• 45% found to be MRSA.

6. TALAN ET AL.
Primary Outcome (ITT)
• Bactrim: 80.5%
• Placebo: 73.6%
Secondary Outcomes
• Subsequent surgical drainage: 3.4% (Bactrim) vs 8.6% (placebo)
• Skin infections at new sites: 3.1% (Bactrim) vs 10.3% (placebo)
• Infections in household members: 1.7% (Bactrim) vs 4.1% (placebo)

7. TALAN ET AL.
Complications
• GIT upset
Bactrim 42% Placebo 37%
• Treatment cessation due to adverse events
Bactrim 1.9% Placebo 0.6%
• No cases of C.Diff

8. Aim: Subgroup analysis for populations guidelines
recommend using antibiotics in.
• >5cm abscess
• cellulitis
• Systemic features
• Immunosuppression (T2DM, CRF)

9. Cure rates higher in all groups treated with Bactrim.
No major difference between
• >5cm and <5cm abscess
• cellulitis >5cm and <5cm diameter
• Immunosuppression (T2DM, CRF)

10. Greatest benefit in
• Subjective symptoms of fevers (16.9%)
• Hx of MRSA (22.9%)
• MRSA grown in culture (20.7%)
(Average improvement 12.2%)

12. DAUM ET AL.
• 2017 USA, Multicentre RCT, Double blind
• 786 patients (Paediatric and Adult)
• 10 days of Bactrim (160/800mg) BD versus clindamycin
(300mg) TDS versus placebo.
• Abscesses <5cm in size.
• Exclusions: obese, multiple lesions, systemically unwell,
major comorbidities (T2DM)
• 49% found to have MRSA.

13. DAUM ET AL.
Primary outcome: clinical cure rates at 19-22 days
• Clindamycin 83.1%
• Bactrim 81.7%
• Placebo 68.9%

14. DAUM ET AL.
Treatment associated adverse events
Clindamycin 21% Bactrim 11% Placebo 12%
• No cases of C.Diff
• 1 hypersensitivity reaction to Bactrim
Fever, rash, thrombocytopenia, hepatitis (self
limiting)

15. • Systematic review and meta-analysis of RCTs.
• 2406 patients.
• 4 studies.

16. Treatment failures
• Antibiotics 7.7% Placebo 16.1%
• NNT 13.5
Lesions at other sites
• Antibiotics 6.2% Placebo 15.3%
• NNT 11

17. Adverse events
• Antibiotics 24.8% Placebo 22.2%
• NNH 23

19. ISSUES
• US studies only.
• Significant amounts of overlying cellulitis in study
populations.
• Rare but serious drug side effects associated with
Bactrim and clindamycin (C. Diff, SJS).
• Changes to resistance patterns of Staph Aureus with
widespread antibiotic use.
• Which drug and what dose?