Historically, the gold standard of first-line therapy for impetigo has been topical treatment. However, its effectiveness has recently been diminished because the causative strains of bacteria are extremely virulent. Additionally, resistant strains of bacteria, most commonly S. aureus, have emerged.

Oral medications that are effective against impetigo include antistaphylococcal penicillins (cloxacillin, dicloxacillin), amoxicllin/clavulanate (Augmentin), and macrolides (although resistance to erythromycin is on the rise). If you do a culture, request a susceptibility report to determine which antibiotics are effective against the specific bacteria involved. Resistance can vary from community to community.

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In an uncomplicated case of impetigo on a healthy immunocompetent patient without underlying skin conditions who lives in an area where bacterial resistance is low, topical therapy alone would be worth a try. However, if the impetigo is widespread or of the bullous type, or if the patient is immunocompromised or has an underlying skin condition, such as atopic dermatitis, consider starting oral antibiotics in conjunction with topical therapy.   

Mupirocin (Bactroban) Once a very popular treatment choice for impetigo, mupirocin is another drug that has succumbed to resistance. When applied to affected areas three times daily for 7-10 days in children older than three months, this pregnancy category B topical drug had been shown to be as effective as oral erythromycin for treatment of superficial, localized, and isolated eruptions.      

Retapamulin (Altabax) A medication belonging to the new antibiotic class called “pleuromutilins,” this ointment was approved by the FDA in 2007 specifically for the topical treatment of impetigo caused by MRSA or S. pyogenes. Retapamulin’s shorter course—twice daily dosing for five days—helps to increase patient compliance. The medication is to be used in patients 9 months of age or older and is classified as pregnancy category B. In a randomized, double-blind, multicentered 14-day study by Koning and colleagues, 139 evaluable patients in the retapamulin group and 71 in the placebo group used topical retapamulin ointment 1% or placebo twice daily for five days (Br J Dermatol. 2008;158: 1077-1082). Based on the primary efficacy end point of clinical response after seven days and using intention-to-treat analysis, retapamulin ointment was superior to placebo (success rate 85.6% vs. 52.1%; P<.0001).   

Cephalexin (Keflex) This first-generation cephalosporin has been one of the most commonly used oral antibiotics in the treatment of impetigo. Cephalexin arrests bacterial growth by inhibiting bacterial cell-wall synthesis and has bactericidal activity against rapidly growing organisms. This agent’s primary activity is against skin flora. It is used mainly for S. aureus that is resistant to erythromycin. The most common adult dosage is 500 mg every six to eight hours for 10 days, while a child’s dosage is 25-50 mg/kg/day every six to eight hours for 10 days, not to exceed 3 g daily. Note that co-administration of Keflex with aminoglycosides increases the potential for nephrotoxicity. In addition, adjusted dosing is necessary for individuals with kidney disease. The only documented contraindication is previous hypersensitivity to Keflex. A category B pregnancy drug, cephalexin is a good choice for women with childbearing potential.

Oral antibiotics for MRSA infections Many antibiotics are effective against MRSA. However, as this bacteria nears epidemic proportions, knowing the resistance patterns in your area is crucial so that you can provide the best empiric treatment, if warranted, while awaiting return of culture results. Many articles have recently recommended the use of trimethoprim/sulfamethoxazole (Bactrim) or tetracyclines for treatment of this resistant bug. Clindamycin can be used, but the risk of Clostridium difficile infection is real, with its resistance rates climbing as well. Ciprofloxacin (Cipro), levofloxacin (Levaquin), rifampin, and linezolid (Zyvox) are other oral options. Rarely, IV antibiotics, such as vancomycin (Vancocin) or gentamicin (Garamycin), along with admission to an emergency department, may be warranted in a case of community-acquired MRSA with severe systemic symptoms.

The use of topical antiseptics, such as Hibiclens soap, has not been proven to provide any additional benefit to the topical and/or oral antibiotic regimen for the affected individual but does help contain the spread of bacteria to others.


Patients with impetigo should wash their hands thoroughly, especially after touching the affected portion of their body. Instruct patients to keep fingernails trim and clean and to change and clean all clothing daily. Prompt washing of open wounds with soap and water is crucial. Most clinicians who practice dermatology prefer not to use neomycin, bacitracin, polymixin B (Neosporin) ointment because of its high allergy potential (even after years of use), but covering the affected area with a bandage is imperative. Advise patients to avoid contact with newborn babies, the elderly, and pregnant women, especially if MRSA is involved. Patients are strongly urged not to visit hospitals or nursing homes until the infection is resolved. MRSA patients should stay at home and not handle food until oral antibiotics have been consumed for 24 hours. Those whose occupation is food-related or medically related should ask their clinician when to return to work.

Good personal hygiene is paramount for treating infected and colonized patients and can also aid in prevention of impetigo. Daily cleansing with antibacterial soap and water that includes the face, hands, and hair is essential. In addition, a daily bath with antiseptic soap, such as Lever 2000, Cetaphil antibacterial soap, or Hibiclens, and weekly bleach baths will keep down the level of staph colonization on the infected person’s body. A bleach bath consists of one to two capfuls of bleach (approximately one to two ounces) in a full bathtub of warm water. Patients should immerse their entire body up to their chin but not including face or scalp for 10-15 minutes at each bath. Patients who have underlying skin disease, such as eczema, with a plethora of superficial and deep fissures, may not be able to tolerate this method of bacterial colonization reduction.

An additional set of rules applies for caregivers of patients with impetigo. Be sure to wash your hands after each patient encounter, a practice that should be a matter of routine. Do not share towels, sheets, and clothing with the infected person. Do not let children play with others who are infected, since their method of “playing” will likely result in the transmission of bacteria.

Mrs. Zajac practices medical and cosmetic dermatology in Bethesda and Germantown, Md. Mrs. Jacobson practices dermatology in Lancaster, Pa., and owns Both are current board members of the Society of Dermatology Physician Assistants.

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All electronic documents accessed June 5, 2009.