Comment: The quality of evidence is downgraded by imprecise results; few patients and wide confidence intervals.
A Cochrane review [Abstract] 1 included 14 studies with a total of 761 subjects. Participant age ranged from 2 to 60 years, and sex ratio was similar. The included studies were conducted in dermatology departments and a paediatric clinic. Study duration ranged from 5 to 26 months. The included studies assessed macrolide antibiotics, an antiviral agent, phototherapy, steroids and antihistamine, and Chinese medicine.
Clarithromycin. There is probably no difference between oral clarithromycin and placebo in itch resolution (RR 0.84, 95% CI 0.47 to 1.52; 1 study, 28 participants) or rash improvement (medical practitioner-rated) (RR 1.13, 95% CI 0.89 to 1.44; 1 study, 60 participants).
Erythromycin. When compared with placebo, erythromycin did not statistically significantly increase rash improvement (medical practitioner-rated) (RR 4.02, 95% CI 0.28 to 56.61; 2 studies, 86 participants). Itch resolution was not measured, but one study measured reduction in itch score, which is probably larger with erythromycin (MD 3.95, 95% CI 3.37 to 4.53; 34 participants).
Azithromycin. Two trials compared oral azithromycin to placebo or vitamins. There is probably no difference between groups in itch resolution (RR 0.83, 95% CI 0.28 to 2.48) or reduction in itch score (MD 0.04, 95% CI −0.35 to 0.43) (both outcomes based on one study; 70 participants). Evidence from two studies indicates there may be no difference between groups in rash improvement (medical practitioner-rated) (RR 1.02, 95% CI 0.52 to 2.00; 119 participants).
Acyclovir. Acyclovir was compared to placebo, vitamins, or no treatment in three trials. Based on one trial (21 participants), itch resolution is probably higher with placebo than with acyclovir (RR 0.34, 95% CI 0.12 to 0.94); reduction in itch score was not measured. However, there is probably a significant difference between groups in rash improvement (medical practitioner-rated) in favour of acyclovir versus all comparators (RR 2.45, 95% CI 1.33 to 4.53; 3 studies, 141 participants). One trial compared acyclovir added to standard care (calamine lotion and oral cetirizine) versus standard care alone (24 participants). The addition of acyclovir did not significantly increase itch resolution (RR 4.50, 95% CI 1.22 to 16.62) and reduction in itch score (MD 1.26, 95% CI 0.74 to 1.78) compared to standard care alone. Rash improvement (medical practitioner-rated) was not measured.
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