19 June 2008

Weird Abscesses

I have seen a lot of abscesses in my career. They're quite different now than they used to be -- in training, in an inner-city program, I used to see lots of IV drug abusers with cutaneous abscesses due to injecting dirty drugs. Those pusbags were hot, red, tense, and exquisitely painful. When lanced, with good local anesthesia, they produced fountains of pus and immediate relief from the pain, and they healed well without antibiotics.

Now, of course, we all know about CA-MRSA, and 99% of the cutaneous abscesses I see are due to this germ. But they look quite different than the "classic" abscesses. Generally, they are notable for a central, shallow pustule, with minimal purulent material, and significant surrounding erythema. You can de-roof the pustule, but you never really get anything out -- just enough to culture -- and evacuating the pus is not sufficient for healing. Antibiotics are always, it seems, necessary.

The MRSA seems different in children, especially infants and toddlers. Those can look similar to the superficial pustules that adults get, but seems to have a much higher incidence of harboring a large subcutaneous collection of pus, which will fountain out under pressure when lanced. The kids seem to be much sicker (febrile, high white counts, etc) and way more likely to require hospitalization.

It's hard to know whether this is a regional thing, or whether I am seeing the typical presentation of the CA-MRSA lesions. Is this consistent with what you all are seeing?


  1. Out of curiosity, does human medicine use regional perfusion with antibiotics for hard-core infections on the limbs? Being involved in equine medicine, I've seen a lot of what are locally called distal limb perfusions (DLP's) in which a tourniquet is applied and an antibiotic (in horses, aminoglycosides are most commonly used, but other classes can be used as well) infused into a vein (or, occasionally, an artery or intraosseous space). The tourniquet is left in place 20-30 minutes.

    DLP's are used for bad wounds in the distal limbs, septic arthritis or tenosynovitis (concurrent with repeated joint/tendon sheath lavage) and acute osteomyelitis.

  2. Nope. A similar technique is occasionally used for regional anesthesia of the upper extremity (commonly referred to as a Bier Block), but people tend to get really whiny when you leave a tourniquet on for a while.

    One advantage of dealing with animals, I guess.

  3. Working in a peds clinic, I've seen a couple cases of MRSA. Talking with the parents, they all said the same thing. It resembled spider-bites.

  4. I'm only a student, but I've clocked a lot of clinic/hospital hours in my current and my pre-med school life, and the MRSA I've seen (both CA and HA in staff) tends to look exactly as you've described. A few times, I've seen kids with non-healing ulcerated pustules, and I've seen a few really wicked cases of post-leg-waxing folliculitis (one of which healed on its own, but left scars). But yeah, lots of erythema, not as much pus as you'd expect, and almost always seems to need antibiotics. Oddly (at least to me), I've seen a number of cases involving the back of the neck (all in the indigent population) - is that something common to the bug in your experience?

  5. Yup, that's my experience too.
    ~your friendly neighborhood pediatrician

  6. Hey, anonymous stole my line!

    The literature supports your observation that in more recent years the strains of MRSA have acquired increased virulence and thus present with more severe symptoms.

    As another public service reminder: Wear face shields, people!

  7. we still don't treat simple abscesses with abx. just i&d. even if they are mrsa.

    midwest er doc.

  8. All I know from experience is that I was hospitalized for over a week thanks to a truly nasty looking MRSA abscess that wound up having necrotic tissue underneath a truly disgusting heap of purulence. (Also hot, red, and exquisitely painful!) Had a few days of IV vanco and then a month on (oral) doxycycline. Totally freaked out both my general MD and the surgeon...luckily I didn't get any systemic symptoms from it, though locally it was a mess! Bleach solution was also partly responsible for the cure, since I had several whirlpool tx with bleach in the water so strong that's all I could smell. All in all, NOT a pleasant experience!

    Luckily this was over a year ago & I've had no recurrence.

  9. The ONLY prospective study of the use of antibiotics for simple abscess post-I&D is now underway. The original stateement that antibiotics are "always necessary" has no grounds in the current evidence base. Cellulitic lesions do require antibiotics.

    Logical MD


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