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Am Fam Physician. 2004;70(9):1680-1681

Clinical Scenario

A five-year-old girl presents with a 4-by-6-cm area of honey-crusted confluent papules of four days’ duration on her face. Your diagnosis is impetigo.

Clinical Question

Which treatments for impetigo are most effective?

Evidence-Based Answer

The topical antibiotic mupirocin is as effective or possibly more effective than oral treatment in patients with limited disease. For practical reasons, oral antibiotics such as penicillins, cephalosporins, and macrolides often are used in patients with extensive disease, but there is insufficient evidence to determine whether topical or systemic antibiotics are more effective. Limited evidence does not support the use of disinfectants.

Practice Pointers

Impetigo is a contagious superficial skin infection most frequently encountered in children, with a peak incidence between the ages of two and six years.1 In fact, impetigo is the most common skin infection in children.2 Causative agents include group A β-hemolytic streptococci (GABHS) andStaphylococcus aureus. The differential diagnosis of nonbullous impetigo includes shingles, cold sores, cutaneous fungal infections, and eczema. The differential diagnosis of bullous impetigo includes thermal burns, blistering disorders, and Stevens-Johnson syndrome. Complications such as cellulitis, lymphangitis, and septicemia are rare and result from spread of the infection. The infection is transmitted via direct contact with the lesion.

Cochrane Abstract

Background. Impetigo is a common superficial bacterial skin infection that is encountered most frequently in children. There is no standard therapy, and guidelines for treatment differ widely. Treatment options include oral and topical antibiotics, as well as disinfectants.

Objectives. To assess the effects of treatments for impetigo, including waiting for natural resolution.

Search Strategy. The authors3 searched the Skin Group Specialized Trials Register (March 2002), Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2002), the National Research Register (2002), MEDLINE (from 1966 to January 2003), EMBASE (from 1980 to March 2000), and LILACS (November 2001). They hand searched the Yearbook of Dermatology (1938 to 1966) and the Yearbook of Drug Therapy (1949 to 1966), referred to article reference lists, and contacted pharmaceutical companies.

Selection Criteria. Randomized controlled trials of treatments for nonbullous and bullous, primary and secondary impetigo were selected.

Data Collection and Analysis. All steps in data collection were done by two independent reviewers. Quality assessments and data collection were performed in separate stages.

Primary Results. A total of 57 trials of 3,533 participants was included; 20 oral and 18 topical treatments were studied. Topical antibiotics showed better cure rates than placebo (pooled odds ratio [OR], 6.49; 95 percent confidence interval [CI], 3.93 to 10.73), and no topical antibiotic was superior to another (pooled OR of mupirocin versus fusidic acid, 1.76; 95 percent CI, 0.69 to 2.16). Topical mupirocin was superior to oral erythromycin (pooled OR, 1.22; 95 percent CI, 1.05 to 2.97). In most other comparisons, topical and oral antibiotics did not show significantly different cure rates, nor did most trials comparing oral antibiotics. Penicillin was inferior to erythromycin and cloxacillin, and there is little evidence that use of disinfectant solutions improved impetigo. The reported number of side effects was low. Oral antibiotic treatment caused more side effects, especially gastrointestinal effects, than topical treatment did.

Reviewers’ Conclusions. Data on the natural course of impetigo are lacking. Placebo-controlled trials are scarce. There is little evidence about the value of disinfecting measures. There is good evidence that topical mupirocin and topical fusidic acid (not available in the United States) are equally or more effective than oral treatment in patients with limited disease. It is unclear if oral antibiotics are superior to topical antibiotics in patients with extensive impetigo. Fusidic acid and mupirocin are similar in efficacy. Penicillin was not as effective as most other antibiotics. Resistance patterns against antibiotics change and should be taken into account in the choice of therapy.

These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (

Because trials in this review included children and adults, the average age of trial participants was much older than that of the typical impetigo patient. In all but two studies, investigators performed bacteriologic investigations to confirm the diagnosis. The main outcome measured in this review was the clinical cure rate after one week of treatment. “Clinical cure” included cure as assessed by the investigator (which was often not defined and sometimes included both improvement and cure after varying lengths of treatment) and relief of symptoms as assessed by the participants. Length of follow-up varied widely in individual studies and sometimes was not specified. Many of the trials studied one treatment for multiple diseases and therefore had few cases of impetigo.

Although impetigo is thought to be a self-limiting condition, studies on its natural history do not exist and are ethically unfeasible. Disinfectants such as povidone-iodine and chlorhexidine have been inadequately studied and have not been compared with placebo. At this time, there is no evidence to support the use of disinfectants as either sole or supplementary treatment for impetigo; this is an area for future research.

Antibiotics are the mainstay of therapy. Physicians first must decide on a route of administration, either topical or systemic, and then on a specific drug. If the area of affected skin is limited, mupirocin is an effective topical therapy; it was more effective than the other topical antibiotics studied (i.e., neomycin, bacitracin, polymyxin B, and gentamicin). There is insufficient evidence to determine whether oral antibiotics are better than topical agents in patients with more extensive disease, although there are obvious practical reasons to choose oral agents if large amounts of skin are involved. Antibiotic categories to consider include penicillins, cephalosporins, and macrolides. Oral antibiotics have significantly more side effects, especially gastrointestinal effects, than topical agents.

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