Antibiotic Topical Gel May Protect Against Lyme Disease

In Phase II/III studies, researchers from Austria, German, and Switzerland found that an antibiotic topical gel can protect against Lyme borreliosis. The results of the study are published in the Lancet Infectious Diseases.

Lyme disease is caused by Borrelia bacteria, most likely B. burgdorferi; more recently, B. mayonii was also found to cause Lyme disease. According to the study authors, approximately 1% to 5% of individuals who are bitten by ticks carrying Lyme borreliosis develop the infection. In Austria, approximately 24,000 individuals are diagnosed with Lyme disease each year, and more than 200,000 cases are diagnosed in Western Europe, alone, according to a recent press release. However, the study authors note that the disease is underdiagnosed by 30%. Therefore, a prevention strategy that can be applied to a broad variety of individuals is strongly needed.

Researchers from institutions in Austria, Germany, and Switzerland conducted studies to investigate if azithromycin antibiotic topical gel can protect against Lyme borreliosis. The researchers conducted a randomized double-blind placebo-controlled study, which enlisted 1371 adult patients from 28 sites across Germany and Austria. The study participants were split equally between a control and an experimental group. Seventy-two hours after being bit by ticks, the individuals in the experimental group received 10% azithromycin topical gel two times a day for 3 days consecutively, while those in the control group received a placebo. (The gel was developed by Ixodes AG, a company in Switzerland.)

Treatment with the topical gel was “well tolerated” by the experimental group and found to have a “good safety profile.” Only 2% of the 505 participants in the experimental group had “treatment failures,” and 2% of the 490 participants in the placebo also had treatment failures, which are defined by the study authors as erythema migrans­—a skin rash characteristic of Lyme disease– seroconversion, or both. Adverse reactions, which were mostly mild, were observed equally among the two groups (175 [26%] of 505 vs 177 [26%] of 490, P = 0.87).

While “none of the [experimental] test subjects went [on] to develop Lyme borreliosis,” seven individuals in the placebo group developed infection, according to a comment made in the press release by Professor Bernd Jilma, MD, from the department of Clinical Pharmacology at the Medical University of Vienna. Dr. Jilma concluded that the azithromycin gel successfully killed the Borrelia in those patients who received it.

According to the World Health Organization, Lyme disease can cause fever, chills, myalgia, and headache, and may cause arthritis in the long run. A number of people believe that, if left untreated, Lyme disease can progress to chronic Lyme disease; however, some doctors believe that there is no such thing as chronic Lyme disease. The Centers for Disease Control and Prevention encourage patients who have completed a full 2-4 week course of antibiotic and are still suffering from lingering symptoms of Lyme disease to confirm with their doctors that there are no additional underlying causes of these symptoms.