Solitary erythema migrans in children: comparison of treatment with azithromycin and phenoxymethylpenicillin

Abstract

Objective: To compare clinical effectiveness and side effects of treatment with azithromycin or phenoxymethylpenicillin in children with solitary erythema migrans.

Methods: Consecutive patients younger than 15 years, referred to our institution in 1998 and 1999 with previously untreated typical solitary erythema migrans, were included in this prospective study. Basic demographic features and clinical data were collected by means of a questionnaire. The efficiency of treatment of acute disease, development of later major and/or minor manifestations of Lyme borreliosis and side effects of treatment were surveyed by follow-up visits during the first year.

Results: Forty-two patients received azithromycin 20 mg/kg/day for the first day followed by 10 mg/kg/day for a further four days and phenoxymethylpenicillin 100,000 IU/kg/day for 14 days. No differences in demographic and clinical pre-treatment characteristics were present in the two groups, with the exception of the duration of erythema migrans before treatment (3 days in the azithromycin group versus 4 days in the phenoxymethylpenicillin group; p = 0.0320). The clinical course during the post-treatment period revealed no significant differences between the two groups in the duration of EM (3 days versus 4 days; p = 0.2471), the appearance of minor manifestations of Lyme borreliosis (17.5% in the azithromycin group versus 24.4% in the phenoxymethyl-penicillin group; p = 0.6252), or in the emergence of major manifestations of Lyme borreliosis (one patient in each treatment group). One year after antibiotic treatment all patients were asymptomatic. Side effects of treatment were observed in 5.3% of patients treated with azithromycin and in 6% treated with phenoxymethylpenicillin. The appearance of "Herxheimer's reaction" at the beginning of treatment was recorded in 7 out of 42 patients (6%) in each treatment group.

Conclusions: Azithromycin and phenoxymethylpenicillin are equally effective in treatment of children with solitary erythema migrans and have comparable side effects.