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Reference: Emerg Med J 2013 May 18 early online, (level 2 [mid-level] evidence)
Skin abscesses are a common complaint in adults and children presenting to emergency departments. The standard treatment is incision and drainage, and there has been evidence since the mid-1980s that adjunctive antibiotics do not appear to be necessary in uncomplicated cases (Ann Emerg Med 1985 Jan;14(1):15). Nonetheless, adjunctive systemic antibiotics are often prescribed. Some of the rationale for this may be related to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) as a significant pathogen, with reports of MRSA present in more than half of abscesses (N Engl J Med 2006 Aug 17;355(7):666). Practice guidelines from the Infectious Diseases Society of America indicate that antibiotics are usually unnecessary, but that additional data are needed to determine the proper role of antibiotics in this setting (Clin Infect Dis 2011 Jun 15;52(12):1468). A new systematic review analyzed data from 4 randomized trials evaluating antibiotic treatment following drainage of uncomplicated skin abscesses in 589 adults and children.
There were 2 trials that used antibiotics potentially active against MRSA (both used trimethoprim-sulfamethoxazole) and 2 trials that used antibiotics active against methicillin-sensitive Staphylococcus aureus, but not MRSA (cephalexin [Keflex] in 1 trial, and cephridine in the other). Patients with complicated abscesses were excluded in all trials. Rates of MRSA infection ranged from 53% to 88%. The primary endpoint was clinical cure at 7 days in 3 of the trials and at 10 days in 1 trial. The 2 trials of trimethoprim-sulfamethoxazole also reported longer term recurrence rates.
There were no significant differences in clinical cure rates (odds ratio 1.17, 95% CI 0.7-1.95) in an analysis of all trials. Trimethoprim-sulfamethoxazole was associated with a nonsignificant reduction in recurrence at 30 or 90 days (risk difference 10%, p = 0.1) in an analysis of 2 trials that included only 52% of the randomized patients. Based on these results, there does not seem to be a role for antibiotics in the management of uncomplicated abscesses. It should be noted that antibiotics still have a role for patients with complicated abscesses (such as those accompanied by systemic symptoms), immunocompromised patients, and for abscesses with significant surrounding cellulitis or in areas difficult to drain, such as the hand.
For more information, see the Skin abscess and Treatment of MRSA skin and soft tissue infections topic in DynaMed.