Three Part Question
In [patients with uncomplicated skin abscesses who have undergone abscess incision and drainage], does [treatment with oral trimethoprim-sulfamethoxazole compared to placebo] [reduce treatment failure at 7 days]?
A man aged 21 years presents to the ED with a 3-day history of increasing redness, swelling and pain in his right thigh. On examination there is an area of fluctuance, approximately 3 cm in diameter, with associated tenderness, on the right anterior thigh. Erythema extends approximately 1 cm beyond the edges of the fluctuance. As the emergency physician, you incise and drain the abscess. You wonder whether a 7-day course of trimethoprim-sulfamethoxazole is really necessary in a healthy person, despite the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infections.
Medline 1966-10/16 using NHS evidence: [(exp trimethoprim sulfamethoxazole/) AND (exp abscess/)] limit to humans and English language 197 records.
The Cochrane Library date of searching 13/10/16: MeSH descriptor: (Trimethoprim, Sulfamethoxazole Drug Combination) explode all trees AND MeSH descriptor: (Abscess) explode all trees 19 records 0 unique articles.
ne hundred and ninety-seven papers were identified using the searches reported above, of which 14 were relevant and 3 were randomised clinical studies that addressed the clinical question. These three randomised trials are summarised in the table
|Author, date and country
||Study type (level of evidence)
|Talan et al|
|1247 of 1265 patients 12 years and older who presented with uncomplicated abscess treated with drainage in five US EDs
Incision and drainage with placebo or incision and drainage with oral trimethoprim-sulfamethoxazole||Multicentre double-blind, placebo-controlled RCT||Clinical cure of abscess at 7 days||73.6% vs 80.5% Difference 6.9% (95 CI 2.1% to 11.7%, p=0.005)||High treatment dose of trimethoprim-sulfamethoxazole (320 and 1600 mg compared with usual 160 and 800 gm
Degree of non-adherence in trial May not be applicable if abscess is not fully drained. Training provided for this RCT
May not be applicable if abscess is not fully drained. Training provided for this RCT|
|Schmitz et al|
|190 of 212 patients, 16 and older, with uncomplicated abscess
Incision and drainage with placebo or incision and drainage with oral trimethoprim-sulfamethoxazole||Double-blind, placebo-controlled RCT||Treatment failure at 7 days New lesions at 30 days||26% vs 17% (p=0.12) 28% vs 9% (p=0.02)||Loss of follow-up Only healthy adults enrolled
No standardisation of incision and drainage technique
|Duong et al,|
|161 patients, aged 3 months to 18 years
Incision and drainage with placebo or incision and drainage with oral trimethoprim-sulfamethoxazole||Double blind, randomized, controlled trial||Treatment failure after 10 days of either||No difference between two groups||Bias: selection 7% lost to follow-up 40% of follow-ups by phone calls|
|New lesion development at 10 days||26.4% vs 12.9%|
There are numerous reports indicating a dramatic increase in skin infections caused by community-acquired MRSA. Surgical drainage of skin abscesses has been the accepted standard treatment. With the emergence of MRSA infections, antibiotics are often recommended after incision and draining. Of the three clinical studies found, only one described improved cure rates of the abscess after treatment with trimethoprim-sulfamethoxazole. However, all three papers describe a decrease in new abscess formation after treatment.
RCT, randomised controlled trial.
Clinical Bottom Line
Trimethoprim-sulfamethoxazole may help with abscess cure, and will decrease abscess formation at new sites.
- Talan DA, Mower WR, Krishnadasan A, et al. Trimethoprim–Sulfamethoxazole versus Placebo for Uncomplicated Skin Abscess. NEJM 2016;374:823–32.
- Schmitz GR, Bruner D, Pitotti R, et al. Randomized Controlled Trial of Trimethoprim-Sulfamethoxazole for uncomplicated Skin Abscesses in Patients at Risk for Community-Associated MRSA Infection Ann Emerg Med 2010; 56:283-287.
- Duong M, Markwell S, Peter J, et al. Randomized, Controlled Trial of Antibitoics in the Management of Community-Acquired Skin Abscesses in the Pediatric Patient Ann Emerg Med 2010;55: 401–7.