It is time to reconsider prescribing “double coverage” therapy with Keflex (cephalexin) and Bactrim (trimethoprim-sulfamethoxazole) in patients with non-purulent cellulitis, which is a superficial skin infection without evidence of pus such as skin abscesses.
Why do providers prescribe “double coverage”?
There is a dogma in medicine and contentious debate that Bactrim is ineffective towards Streptococci such as group A Streptococcus (GAS). Moreover, many providers are trying to cover for MRSA empirically.
What should providers know?
There is supportive laboratory data that Bactrim has in vitro activity against GAS and should be considered for treatment in non-purulent cellulitis2 . Also, covering for MRSA empirically is unnecessary unless there is penetrating trauma such as intravenous drug use, nasal colonization of MRSA, purulent drainage, or previous MRSA infection1. Interestingly, there was a recent multi-center, double-blind, randomized, and placebo-controlled trial, that compared the use of Keflex and Bactrim to the use of Keflex alone, which did not result in higher rates of clinical resolution of cellulitis3. Of course, patients should be given a proper follow-up and
instructions to return for a visit if treatment failure does occur.