Treatment of uncomplicated skin infections: A novel algorithm for dermatologists

September 1, 2005

Regardless of the pathogen and sensitivity pattern, drainage is the foremost major therapeutic intervention for a simple abscess.

Uncomplicated skin and skin structure infections (uSSSIs) are among the most common infections treated by dermatologists.

If diagnosed early and treated appropriately, these infections are almost always curable, but left untreated, they can lead to serious complications. As with other therapeutic categories, there is a need for treatment guidelines for uSSSIs to help providers make the best decisions for their patients' needs.

Wide range

While those associated with a collection of purulent material require surgical incision and drainage, others respond to antibiotic therapy alone. The major bacteria are staphylococcus aureus and streptococcus pyogenes, but there are other pathogens that may cause cutaneous infection; these include some Gram-negative organisms. Among the most important issues, physicians need to understand the range of conditions classified as uncomplicated infections, including most cutaneous infections in patients with well-controlled underlying illness, like diabetes mellitus. Most uncomplicated skin and skin structure infections in well-controlled diabetics as well as HIV-positive patients respond to therapy in a manner similar to infections in other populations.

New algorithm

A new treatment algorithm has been developed for the initial empiric treatment of uncomplicated skin and skin structure infections.

The development was led by a team of specialists with expertise in the areas of cutaneous infections, pediatric skin infections and diabetic foot infections, under the guidance of Dr. Richard Scher of Columbia University. The initial draft of the algorithm was directed at empiric therapy in the primary care setting, and does not address surgical prophylaxis, leg ulcers or refractory infections. Future versions directed toward dermatologists will address these issues.

First step

The first step in the treatment of uSSSIs, which involve collections of purulent material, should be incision and drainage of abscesses.

Regardless of the pathogen and sensitivity pattern, drainage is the foremost major therapeutic intervention for a simple abscess. For uSSSIs that require oral antibiotic therapy, the appropriate choice of an antibiotic is based on a combination of factors, including safety, compliance, efficacy and cost. This algorithm offers a structure of the most effective antibiotic options for these infections.

Even when a culture is performed, a physician's initial treatment decision for uSSSIs is empiric, unless all therapy will be withheld until the culture results are available. Among the antibiotic options listed in the guidelines, cephalosporins are commonly used because of their long-term favorable safety profile and tolerability. Other alternatives listed include a semi-synthetic penicillin or a penicillin derivative with a penicillinase inhibitor such as clavulanate. Alternatives such as tetracycline, sulfa, clindamycin, vancomycin and some newer, more expensive agents are particularly useful in special populations at high risk for resistant pathogens, or when a culture shows a non-susceptible pathogen and the patient is not improving.

Third-generation and extended-spectrum cephalosporins, such as cefdinir, do not share the risk that other cephalosporins pose, since they do not share the same side chain and have little risk of allergic reaction, even in patients with type 1 allergy to a penicillin. They are an appropriate and safe choice for patients with penicillin allergy. An extended-spectrum cephalosporin can also be helpful when a range of pathogens may cause the infection.

Increased role

Updates to the algorithm emphasize the role of drainage for abscesses, as well as the role of dermatologists as consultants for refractory infections. Dermatologists should consider the importance of clinical re-evaluation if a culture shows a pathogen resistant to the chosen antibiotic.

Clinical improvement may occur even in the face of resistance, so the clinical reassessment is important. It is important, as always, to treat the patient, not the lab result.

Separate algorithms are under consideration for development for antibiotic prophylaxis during surgical procedures (prophylaxis against wound infection as well as SBE prophylaxis), and for leg ulcers. Using this new set of guidelines from leading experts in the field, dermatologists now have assistance to make more informed decisions on the best course of action for their patients with uncomplicated skin infections.

Dr. Elston is with the Geisinger Medical Center, Danville, Pa.

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