skin abscesses treatment

review article in new england journal this week on management of skin abscesses in era of methicillin-resistant staph aureaus MRSA (see skin abscesses mrsa review nejm 2014 in dropbox or DOI: 10.1056/NEJMra1212788). both the incidence of skin abscesses overall and the % of MRSA have increased over time. a few comments:

    --diagnostic accuracy is not great: eg, a study of 126 adults with cellulitis where ER MD felt abscess not evident, ultrasound found abscess in 50%

    --treatment of abscess is primarily I&D

    --there may be more rapid healing if the I&D incision is closed vs leaving it open (studies mostly in the anogenital area, showing half the healing time and no diff in recurrences). should consider primary closure if incision >2cm. [goes against conventional wisdom that needs to be open to continue draining]

    --no data as to whether to irrigate the wound, and data on whether packing helps is unclear (a couple of very small studies done, one in adults showing more pain but no outcome difference, one in kids found more frequent subsequent drainage and antibiotic treatment in those not packed)

    --antibiotics. in 2008, 63% of abscesses were from community-associated MRSA. 15% in MSSA, 2% b-hemolytic strep, 20% other. but cure rates for just I&D alone are in the 85% range. a study in kids found no diff if give tmp/smx vs placebo after I&D, though some decrease in new lesion development. so, Infectious Diseases Society of America recommends systemic antibiotics for patients with extensive disease (multiple sites), rapidly progressive dz, signs/symptoms of systemic illness, immunosuppression, very young or old, abscess in difficult area to drain, associated septic phlebitis, or drained abscess not responding just to I&D.

    --empirical antibiotic therapy when chosen should cover MRSA, ie first choice of tmp/smx 1-2 DS tabs bid. some resistance to clinda and tetras, but can do clindamycin 300-450 tid, doxycylcine 100 bid or minocycline 200, then 100 q12h.

    --if cellulitis alone, more likely to be strep (difficult to really know the organism if just cellulitis, though), and TMP/SMX and tetracyclines less active. clinda may be better choice. and my experience is that TMP/SMX, which has limited activity against strep, typically works well with cellulitis (though i never do ultrasound to rule-out small abscess...). if severe cellulitis, might cover with TMP/SMX plus cephalexin. there are no great data for these suggestions from clinical trials, and some trials are currently ongoing.

so, this brings up a few issues. even though it is commonly incorrect to conclude that an abscess is not present without the aid of an ultrasound, those of us in the community cannot typically get an ultrasound easily. unless the patient has severe infection needing hospitalization, we treat them by I&D if there is an evident abscess present, will occasionally needle it if not sure (though sometimes purulent collections can be quite viscous and can be missed with a needle), and (probably more often than is necessary) prescribe antibiotics. my experience is that small abscesses/collections often resorb with heat and antibiotics without I&D.