Cochrane for Clinicians

Putting Evidence into Practice

Interventions for Impetigo

JULIE SCOTT TAYLOR, M.D., M.SC., Brown Medical School, Providence, Rhode Island

This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been systematically reviewed by an AAFP-approved source. The practice recommendations in this activity are available online at http://www.cochrane.org/cochrane/revabstr/ab003261.htm.

The Cochrane Abstract below is a summary of a review from the Cochrane Library. It is accompanied by an interpretation that will help clinicians put evidence into practice. Julie Scott Taylor, M.D., M.Sc., presents a clinical scenario and question based on the Cochrane Abstract, along with the evidence-based answer and a full critique of the abstract.

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 beta-hemolytic streptococci (GABHS) and Staphylococcus 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.

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.

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 (www.cochrane.org).

The Author

JULIE SCOTT TAYLOR, M.D., M.SC., is assistant professor of family medicine and director of predoctoral education in family medicine at Brown Medical School, Providence, R.I.

Address correspondence to Julie Scott Taylor, M.D., M.Sc., Department of Family Medicine, Memorial Hospital of Rhode Island, 111 Brewster St., Providence, RI 02860 (e-mail: Julie_Taylor@brown.edu). Reprints are not available from the author.

REFERENCES

---

Cochrane Briefs

Donepezil in the Treatment of Vascular Dementia

Clinical Question

Is donepezil effective in the treatment of vascular dementia?

Evidence-Based Answer

Donepezil in a dosage of 10 mg daily provides a small benefit in patients with mild to moderate vascular dementia and generally is well tolerated.

Practice Pointers

Donepezil, a cholinesterase inhibitor, is somewhat effective in the treatment of mild to moderate cognitive impairment caused by Alzheimer's disease. Malouf and Birks examined the evidence from two similar manufacturer-sponsored studies of donepezil in a total of 1,219 patients with vascular cognitive impairment (sometimes called "multi-infarct dementia" or "vascular dementia"). Both studies were randomized, double blinded, and placebo controlled. Validated diagnostic criteria were used to identify patients with probable vascular dementia. Given the challenge of diagnosing dementia subtypes before death, however, a substantial number of patients probably had mixed vascular and Alzheimer's dementia.1

Patients who took donepezil performed slightly better on tests of cognitive function, such as the Mini-Mental State Examination (weighted mean difference, 1.2 points at 24 weeks on this 30-point scale) and the Alzheimer's Disease Assessment Scale cognitive subscale. Patients who took the 10-mg dosage did better than those who took the 5-mg dosage. Patients who took the 10-mg dosage (but not the 5-mg dosage) also did better than control patients on the Clinical Dementia Rating scale. There was no difference between groups on the Alzheimer's Disease Functional Assessment and Change Scale, which focuses on activities of daily living. Compared with the lower dosage and placebo, the 10-mg dosage was associated with more adverse events (odds ratio for at least one adverse event, 1.95; 95 percent confidence interval, 1.20 to 3.15; P = .007). Most adverse events were minor, and the pooled dropout rate and the rate of severe adverse events were similar between groups.

MARK H. EBELL, M.D., M.S.

Malouf R, Birks J. Donepezil for vascular cognitive impairment. Cochrane Database Syst Rev 2004;(3):CD004395.

REFERENCE

NSAIDs vs. Opiates for Pain in Acute Renal Colic

Clinical Question

Are nonsteroidal anti-inflammatory drugs (NSAIDs) or opiates more effective for pain relief in patients with acute renal colic?

Evidence-Based Answer

Data from randomized controlled trials comparing NSAIDs with opiates show that NSAIDs are associated with lower pain scores, less need for additional rescue medication, and less vomiting (particularly when compared with meperidine).

Practice Pointers

Acute renal colic is one of the most painful conditions and often is associated with nausea and vomiting. Holdgate and Pollock identified studies that compared NSAIDs with opiates in adults with acute renal colic (fewer than 12 hours' duration) and moderate to severe pain. They found 20 studies that included a total of 1,613 patients and compared a total of five NSAIDs and five opiates (each study compared one opiate with one NSAID).

Study quality was mediocre; although most studies blinded either patients or outcome assessors during the study period, only five studies clearly concealed allocation at the start of the study, and only three definitely used intention-to-treat analysis. Data from the trials could not be combined statistically because of differences in methodology and wide variability in results.

Pain scores were reported in 13 studies. Ten studies found that patients who took NSAIDs had lower pain scores; two studies found no difference, and one study reported lower pain scores in patients who took opiates. There was no difference between treatment groups in complete pain relief at 30 or 60 minutes. Additional "rescue" analgesia was needed more often in patients randomized to opiates (25.4 versus 18.9 percent; P = .007; number needed to treat, 15). Vomiting was more common in patients randomized to opiates (19.5 versus 5.8 percent; P < .00001; number needed to harm, seven). Meperidine caused more vomiting than other opiates; there was no difference in the risk of vomiting between other opiates and NSAIDs.

The Institute for Clinical Systems Improvement's guideline on acute pain management suggests that NSAIDS are often adequate for mild or moderate pain.1 It recommends that opioids be added to pain therapy in these patients only if pain is not controlled adequately with NSAIDs alone.

MARK H. EBELL, M.D., M.S.

Holdgate A, Pollock T. Nonsteroidal anti-inflammatory drugs (NSAIDs) versus opioids for acute renal colic. Cochrane Database Syst Rev 2004;(3):CD004137.

REFERENCE

---

Copyright © 2004 by the American Academy of Family Physicians. This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

---

---