Skin (staphylococcal) abscesses (boils) are often treated with antimicrobials, but are they really needed? The New England Journal of Medicine recently presented a case vignette and asked prescribers to weigh in on whether they thought antibiotics were needed or if incision and drainage alone were enough. The current Australian recommendations (from the Therapeutic Guidelines) are that most lesions can be treated with incision and drainage alone. Antibiotic treatment is required, in addition to incision and drainage, if there is spreading cellulitis or when systemic symptoms are present. It is recommended to perform microscopy and cultures on all lesions if antibiotic therapy is considered, due to the rapid increase in the incidence of community-associated methicillin-resistant S. aureus (CA-MRSA) and the difficulty of its clinical diagnosis. If antibiotics are required empirical therapy with di/flucloxacillin is recommended. Modify therapy based on clinical response to empirical therapy and the results of cultures and susceptibility testing. Even if CA-MRSA is isolated, empirical therapy may be adequate depending on the response to drainage. Treatment for 5 days is generally sufficient, but a longer duration of therapy may be required for patients who are slow to respond or have a more severe infection.
While previous studies have not shown a benefit with antibiotic treatment a study was published in the same issue of the NEJM which suggested that abscesses in areas with a high prevalence of community acquired MRSA had a significantly higher rate of successful treatment when co-trimoxazole was prescribed, although the per protocol cure rate without antibiotics was high (86%). There are a few issues with this study (there may have been enrolment bias and a dose of 320/1600mg twice daily of co-trimoxazole was used, even though 180/800mg twice daily has been shown to reach concentrations that are effective against MRSA) so it is not clear if a change in practice is warranted.
So what did the people say in the NEJM survey? The majority of responders felt that incision and drainage alone were adequate to treat abscesses in an otherwise well patient with a small lesion, mirroring the recommendations in the Therapeutic Guidelines. The responses contain some sage advice from experienced physicians from around the world and are worth a look.
Perhaps the biggest issue is to intervene effectively for those patients or families suffering from recurrent boils / skin infection to prevent recurrence. Treating underlying skin conditions, regular bleach bathing and potentially staphylococcal decolonisation can all be considered. See this posting.