May 17, 2023
A Short Course of Doxycycline for the Treatment of Erythema MigransReviewed by Zeina Kanafani, MD, MS, FIDSA
Lyme borreliosis is a vector-borne pathogen endemic to parts of the United States and Europe and can manifest early as a cutaneous lesion of erythema migrans. Based on the available evidence, oral doxycycline for 10-14 days has been a cornerstone in the treatment of erythema migrans. In the present study, the investigators evaluated whether a 7-day course of doxycycline would be an effective therapeutic option for the rash.
The randomized open-label noninferiority trial was conducted at a teaching hospital in Ljubljana, Slovenia. Patients with a solitary lesion of erythema migrans based on the European criteria were randomized 1:1 to receive doxycycline at 100 mg orally twice daily for either 7 or 14 days. Patients were followed for up to 12 months following enrollment. Researchers classified treatment outcomes as complete response, partial response, or treatment failure, with partial responses and failures considered unfavorable responses. The primary efficacy endpoint was the difference in treatment failure at 2 months with a noninferiority margin of 6%.
The study population consisted of 150 patients randomized to the 7-day arm and 150 patients randomized to the 14-day arm, with 294 patients evaluable at 2 months’ follow-up. In the per-protocol analysis, treatment failure at 2 months’ follow-up was recorded in 5/147 (3.4%) of evaluable patients in the 7-day treatment arm and in 3/147 (2%) of evaluable patients in the 14-day treatment arm (difference, 1.4%; upper bound of 95% confidence interval [CI], 5.2%; P =.64). Comparable data were obtained in the intention-to-treat analysis (difference, 1.5%; upper bound of 95% CI, 5.5%; P = .64). There was no difference between the 7-day and 14-day course in the median time to resolution of the erythema migrans lesion or in the proportion of patients with unfavorable outcomes (partial response or treatment failure). Factors independently associated with an unfavorable response included being female and the presence of Lyme borreliosis-associated symptoms at enrollment. Treatment duration was not predictive of unfavorable outcomes in the regression model. Patients in both arms tolerated doxycycline well, with treatment discontinuation rates of 1% in each group.
In this study, a short 7-day course of doxycycline was therefore noninferior to a 14-day course in adult patients with solitary erythema migrans. The results provide evidence for shortening treatment durations in such cases without compromising treatment efficacy.
