Roberts, James R. MD
Evidence-based data on ED interventions for cutaneous abscesses just don't exist; there is only tradition, personal opinion, and handed-down rituals. Suffice it to say, standard fare seems to be wide skin incision, cavity irrigation, breaking up loculations, gauze packing, a return visit for potentially more packing, and healing without suture closure. Old habits are hard to break, but the very cool loop drainage technique I championed in previous columns is a nifty substitution for I&D.
I pontificated, with a modicum of supporting data, that for a small easily drained abscess, gauze packing is unnecessary and does not effectuate a cure, but this intrusive therapy does dole out unnecessary pain and inconvenience to the patient and mandates repeat ED visits to an already untenably crowded ED. Other countries favor immediate suture closure of even large drained abscesses. But what about the age-old issue of when and how to use antibiotics for a cutaneous abscess? More scientific evidence is available on the use — or more often, the nonuse — of routine antibiotics. A MRSA abscess was once considered a hellacious and widespread clinical scourge and the bane of the fast track that forecasted serious trouble. Early recommendations plied such patients with copious antibiotics post-I&D.
Now the general consensus is that physicians likely provide too many antibiotics to too many patients, even to those harboring MRSA in the depths of the abscess cavity (as most of them now exhibit). I will attempt to put into perspective the current gospel by no less an authority than the erudite Infectious Diseases Society of America, which recently offered a treatise on skin infections in the MRSA era. This article provides the clinician with a reasonable approach based on the best available evidence. The guidelines seem to make sense, at least for now.
Clinical Practice Guidelines by the Infectious Diseases Society of America for the Treatment of Methicillin-Resistant Staphylococcus Aureus Infections in Adults and Children
Liu C, Bayer A, et al
Clin Infect Dis
This summary of evidence-based guidelines for managing patients with MRSA skin infections offers mostly level A recommendations: “good evidence to support recommendations for or against use.” These are intended to be guidelines for health care providers who treat skin and soft tissue infections, but it also includes recommendations for a variety of nasty MRSA-related clinical felons, including bacteremia, endocarditis, and osteomyelitis. I will concentrate on the recommendations for cellulitis and abscess. Apparently CA-MRSA skin and soft tissue infections, compared with less nefarious organisms, do not seem to be of great concern to these authors. Much of the disastrous bloom is off the CA-MRSA rose.
General Cutaneous Abscess Treatment: Recommendation: “For a cutaneous abscess, incision and drainage is the primary treatment.” I&D alone is “likely to be adequate” for simple boils or abscesses. Unfortunately, these guidelines still continue to hedge by stating that additional data are needed to further define the role of antibiotics, if any, in this setting. Certainly our ED experience bears out this axiom. A more gutsy or definitive endorsement seems reasonable because this is a level A recommendation. No comments are made at all on the role of adjunctive interventions, such as abscess packing.
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Antibiotic Therapy: Antibiotics are recommended for abscesses associated with conditions listed in the table. Some of the antibiotic-worthy scenarios are clinical judgment calls, as they certainly should be, and are difficult to define precisely.
These are not new or profound recommendations for antibiotics. Most are familiar indications and practice, and favor the generous use of antibiotics for many skin infections. Antibiotics would be recommended for many ED patients under these guidelines because most denizens of the ED fit criteria that predispose them to abscesses and make them less than uncomplicated or readily cured individuals. Antibiotics effective against CA-MRSA are the predominant antimicrobial players in these guidelines. It's noteworthy that clindamycin gets the nod as appropriate for most circumstances.
Purulent Cellulitis: Purulent cellulitis is a term that is not in common use outside the ID world. It's essentially staph-induced cellulitis, and most EPs rarely see it. Most cellulitis frequenting the ED is attributed to beta-hemolytic streptococcus. Purulent cellulitis is associated with drainage or exudates in the absence of a defined or drainable abscess. This is to be differentiated from the dry, hot, red, tender, swollen skin in the absence of pus or garden-variety cellulitis. The IDSA recommends empirical therapy for CA-MRSA pending culture results. If one is covering for MRSA under these circumstances, additional empirical therapy for beta strep is unnecessary, according to the IDSA. CA-MRSA-specific antibiotics alone are sufficient because they also eradicate strep. In short, pus or exudate equals staph, and these days that staph is CA-MRSA. A five- to 10-day course of therapy is recommended, but should be individualized based on response. Antibiotic options for CA-MRSA cellulitis are listed in the table.
Non-Purulent Cellulitis: Beta-hemolytic streptococcus commonly causes cellulitis but not purulent cellulitis. An empirical beta-lactam alone for five to 10 days is sufficient for this infection. Some clinicians routinely treat all cellulitis for CA-MRSA and Group A strep. I see a Keflex/Bactrim combination often used as an initial choice for non-purulent cellulitis. I cannot see the validity of this nor does the IDSA, and simple cellulitis need not prompt CA-MRSA coverage. Curiously, however, and inexplicable to me, the IDSA then lists combination antibiotics as well as linezolid for non-purulent cellulitis antibiotic choices. (See table.) The best choices are clindamycin or tetracycline alone if one wants to cover CA-MRSA and strep cellulitis with a single antibiotic. I don't see tetracycline used much at all, and it seems to have been forgotten as a reasonable treatment for skin and soft tissue infections by EPs.
Cultures: The IDSA recommends cultures of abscesses or other purulent forms of skin and soft tissue infections only if a patient is being treated with antibiotics, if the local infection is severe, if there are signs or symptoms of systemic illness, or when a patient does not respond to initial therapy. Traditionally, one does not culture a simple cutaneous abscess because they are readily cured with I&D alone. The IDSA guidelines support not culturing a simple abscess even in the CA-MRSA age and even if the abscess was thought to be caused by MRSA, as most are.
This stance is somewhat different from when we first encountered MRSA abscesses and culturing habits changed dramatically. Everyone was cultured, and everyone got antibiotics. Not so currently. It really makes no sense to always culture an abscess that is not going to be treated with an antibiotic. As I see it, the main reason for taking a culture is to check your antibiotic regimen after starting empiric therapy. But one can make a cogent argument for culturing borderline abscesses that are not covered with antibiotics, with the tactic of having a culture available later if the patient returns or requires further therapy, antibiotics, or even admission. It's certainly nice to have a culture in hand when you are trying to sell an infection to the admitting team and to be ahead of the curve regarding selection of antibiotics. In reality, however, all admitted skin and soft tissue infections should be covered for CA-MRSA.
It is prudent to empirically treat an admitted patient with a skin and soft tissue infection for MRSA, but some clinicians still give beta beta-lactams as initial therapy. By consensus, this is a mistake these days. Methicillin-sensitive staph is still out there, and causes about 20 to 30 percent of staph skin and soft tissue infections, but one must treat hospitalized patients for MRSA first and then change the antibiotic if cultures deem it appropriate. One does not want to be treating any serious skin and soft tissue infection, likely caused by some staph species, with an antibiotic that will not cover CA-MRSA. Empiric antibiotics choices for the inpatient therapy of skin and soft tissue infections are presented in the table.
Comment: These are guidelines by a prestigious organization, and the clinician should at least know what's recommended and supported by the infection gurus. Most ID mavens don't work in the ED and likely would never drain a cutaneous abscess or deem cellulitis ID consult-worthy, but emergency physician David Talan, MD, a member of the EMN editorial board, was one of the authors of the IDSA guidelines.
If you are questioned about ED skin and soft tissue infection care, you should be able to support it with these guidelines or at least offer a reasonable explanation why you deviated from them, imperfect though they are. Essentially, you are practicing in the dark if you don't know the guidelines. And it would be fitting to be able to explain why your own personalized approach constitutes good medicine if you know the guidelines and deviate from them.
We can convince ourselves that not all drainable and localized infections require antibiotics, but it still may be a hard sell to patients. Very few diabetics will think you are providing adequate care for any of their soft tissue infections if you don't give them an antibiotic. Diabetics do harbor resistant and difficult-to-cure organisms, their immune state is compromised, and they have always been identified as individuals requiring antibiotics above and beyond standard use for an immunocompetent cohort. Few infections are regarded as minor to a diabetic, and you need to work more shifts if you have not seen a seemingly simple skin infection go bad rather quickly in a diabetic. I don't think you can convince most clinicians, few patients, and not a single juror that treatment was proper if a diabetic patient has a bad outcome after presenting to the ED with an infection and not being treated with antibiotics. No data support that contention, only tradition, but it may be best to be a traditional clinician in these cases.
Likewise, older patients and those with conditions such as hepatitis, HIV, and alcoholism have been targeted as requiring antibiotics for skin and soft tissue infections because of their compromised state. I have been unable to find any researcher brave enough to randomize immunocompromised patients with soft tissue infection to antibiotics versus no antibiotics. These patients are always excluded. Likely, that study will never be done.
Management of Recurrent MRSA Skin and Soft Tissue Infections: Clinicians and patients alike are frustrated by recurrent MRSA infections. Recurrences have usually been considered because of a carrier state or recurrent exposure to another MRSA source. The IDSA suggests that patients with recurrent MRSA skin and soft tissue infections be educated on the germ therapy of disease, with appropriate personal hygiene information, such as hand washing, and not allowing pus or yucky infected bandages to come in contact with an uninfected individual. CA-MRSA is not as contagious as the flu, but it's prudent to warn a patient that CA-MRSA is one infection you can pass on to a close contact, although such warnings have not always been heeded by those with Neisseria gonorrhea, Chlamydia, herpes, and HIV. Environmental hygiene is also recommended, such as cleaning home areas (countertops, door knobs, bath tubs, toilet seats). Good luck with that suggestion.
The recommendations appear to be lacking scientific clout with regard to decolonization. Such patients are probably best referred to a primary care clinician or an infectious disease specialist after the second or third MRSA infection, but one can consider initiating decolonization in the ED. Efforts are mainly focused on nasal decolonization. The nose appears to be a friendly home for many CA-MRSA infections, and applying mupirocin ointment (Bactroban) BID for 10 days into the nostrils garnered a level C-3 recommendation. This is hardly strong science, but it's something that can be tried. Patients love such advice. Whole body wash decontamination with antiseptic solutions, such as chlorhexidine (Hibiclens) daily for five to 10 days or dilute-bleach baths have been recommended. Most patients won't sit in Clorox, but a quarter cup per quarter tub of water, as a soaking bath for 15 minutes twice weekly, for about three months can be considered. I have been giving chlorhexidine solutions to cover the body from head to toe daily for about a week. It is not always possible to keep MRSA from the colonizing the human body, despite these aggressive attempts.
It might be tempting to provide two to three months of antibiotics in an attempt to decolonize MRSA, but this is generally not recommended. You first need a culture, then can provide the appropriate antibiotic plus rifampin. This may be considered for chronic recurring infections despite decolonization attempts. This is also best provided by a primary care physician or ID expert.
So where do we stand on treating abscesses in the CA-MRSA era? It seems reasonable to provide standard abscess care, whatever that might be in today's environment, to those with simple cutaneous abscesses, and eschew routine cultures and antibiotics. Consider a culture if your clinical gestalt leads you to believe that this patient might not be cured, if the infection is borderline in size, or if it qualifies from the other caveats mentioned. You can rethink the antibiotic issue, with culture results in hand, at the first follow-up visit.
There is certainly room for a clinical judgment call in antibiotics for initially treating abscesses. An all-or-nothing approach is plain silly. The conditions favoring the use of antibiotics are listed in the table, and it is prudent to consider these when crafting a decision but based on the individual scenario. It is likely that we will never solve the question of antibiotics versus no antibiotics in the immunocompromised patient who would otherwise not receive antibiotics if he had a normal immune system. Use your best judgment on these, with a strong bias toward a short course of antibiotics in high-risk patients. Chose clindamycin for all comers, both inpatient and outpatients, when in doubt.
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IDSA: Antibiotics after I&D of an CA-MRSA Abscess
Antibiotics for treating a cutaneous abscess is predominantly a clinical judgment call. No standards are universally agreed upon and no data rigorously support antibiotic use for every specific scenario. Definitive and curative therapy for a simple abscess in an immunocompetent patient is drainage of purulent material alone. It is generally agreed that a readily drained abscess (even infected with CA-MRSA) in a healthy and immunocompetent individual does not require routine antibiotic administration. Importantly, however, antibiotic therapy is considered prudent and supported by the experts in some conditions.
* Severe or extensive disease (e.g., involving multiple sites of infection) or rapid progression in the presence of associated cellulitis
* Signs and symptoms of systemic illness
* Associated comorbidities or immunosuppression (diabetes, HIV, neoplasm, etc.)
* Extremes of age (not specified)
* Abscess in area difficult to drain completely (face, hand, genitalia)
* Associated septic phlebitis
* Lack of response to incision and drainage alone
Source: Clin Infect Dis 2015;52(3):1.
Antibiotic Selection for Outpatients
Abscess or purulent cellulitis caused by CA-MRSA1
* Clindamycin: 300-450 mg TID
* Trimethoprim/sulfamethoxazole (TMP/SMX): 1-2 DS tabs BID2
* Doxycycline: 100 mg BID3
* Linezolid: 600 mg BID
1. Termed equally effective by the IDSA.
2. Note the recommendation for up to two tabs per dose.
3. Not for children under 8 years old or during pregnancy.
* Beta lactam alone (e.g., cephalexin or dicloxacillin)1
* Clindamycin alone
1. Consider adding TMP/SMX or a tetracycline if covering for beta-hemolytic streptococci and CA-MRSA.
Empirical antibiotics for admitted patients with skin and soft tissue infections1
* Vancomycin: 15-20 mg/kg/dose, every 8-12 hours
* Linezolid: 600 mg BID
* Daptomycin: 4 mg/kg/dose daily
* Telavancin: 10 mg/kg/dose daily
* Clindamycin: 600 mg TID
1. All medication administered intravenously.
Source: Clin Infect Dis 2015;52(3):1.
Reader Feedback: Readers are invited to ask specific questions and offer personal experiences, comments, or observations on InFocus topics. Literature references are appreciated. Pertinent responses will be published in a future issue. Please send comments to firstname.lastname@example.org.
Dr. Roberts: Thanks for the review. What function does the loop-drain truly play in the I&D process? What are we trying to achieve, prevent, and promote? Thank you. — Iris Eisenberg, MD, MPH, Jacksonville, FL
Dr. Roberts responds: The loop technique is designed to be a total cure for a cutaneous abscess, from start to finish, without the need for incision or packing. The punctures starts pus drainage, the loop keeps it draining, and when you remove the loop, the punctures close over, and you're done.
Dr. Roberts: Do you recommend loop drainage for infected sebaceous cysts? It seems like the technique wouldn't permit removal of the sebaceous material, which is the nidus for the infection. — Matthew Perl, MD, San Diego, CA
Dr. Roberts responds: You make a good point. I have no personal experience with this technique for an infected sebaceous cyst, but one can usually squeeze out the sebaceous material, so perhaps making a bigger incision might work. The capsule often needs removal or the cyst will return. I would revert back to a traditional I&D if I were positive it was a sebaceous cyst.
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