According to the Centers for Disease Control and Prevention, Lyme disease is the fastest growing vector-borne disease, affecting approximately 300,000 Americans every year. It is caused by the spirochete, Borrelia burgdorferi which is transmitted to humans by the deer tick. Lyme disease is often an overlooked diagnosis for myriad reasons, including inaccurate test results.
We all know that the best way to treat any disease is by preventing it. The following measures are recommended as tools to prevent infection: personal protective wear, repellents, and removal of the attached tick. Recommended repellents include DEET, picaridin, IR3535, oil of lemon, eucalyptus, para-Menthane-3,8-diol (PMD), 2-undecanone, and permethrin. If a tick is found, it should be removed promptly by mechanical measures, such as with tweezers. The tweezers should be inserted between the tick body and skin to ensure removal of the entire tick. Burning an attached tick or applying a noxious chemical to the tick is not recommended.
Diagnosing Lyme disease is often difficult given that tests can be negative for some time after a tick bite, even when the infection is present. There is good evidence to show that submitting the removed tick for identification is good practice. However, there is no evidence supporting testing the removed tick for the presence of Borrelia burgdorferi as it does not reliably predict infection in humans. It also is recommended to avoid testing asymptomatic people following a tick bite.
Following a high-risk tick bite, adults and children can be given prophylactic antibiotics within 72 hours. It is not helpful for low-risk bites. If the risk level is uncertain, it is better to observe before giving antibiotics. For adults, a single 200-mg dose of doxycycline can be given. In children, 4.4 mg per kg of body weight, up to 200 mg max, can be used for those under 45 kg.
For patients with a tick exposure and erythema migrans, a clinical diagnosis of Lyme disease can be made without further testing. If the clinical presentation is not typical, it is recommended to do an antibody test on an acute phase serum sample followed by a convalescent serum sample in 2-3 weeks if the initial test is negative. Recommended antibiotics for treatment include doxycycline for 10 days or amoxicillin or cefuroxime for 14 days. If a patient is unable to take these, azithromycin may be used for 7 days.
The guidelines also make recommendations regarding testing for Lyme neuroborreliosis, for which neurologic presentations, for adults with psychiatric illnesses, and for children with developmental/behavioral/psychiatric disorders. They further make recommendations for treatment of Lyme disease involving the brain or spinal column, facial nerve palsy, carditis, cardiomyopathy, and arthritis, which are beyond the scope of this discussion.
As family doctors, we are often the first ones patients call upon after a tick bite. We are the ones who diagnosis and treat Lyme disease, so it is imperative that we stay up to date with current clinical guidelines and practice evidence-based medicine. These most recent guidelines from several specialty societies can provide the answers to many of our patients’ questions. They also serve as a great tool to help with our clinical decision-making regarding tick bites. Lyme disease can be a scary infection for patients but, if we offer them the recommended measures, it doesn’t have to be.
Dr. Girgis practices family medicine in South River, N.J., and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, N.J. You can contact her at.