This post was written by Michael Davis, DO, Parkview Infectious Diseases.
John and Kara went for their weekly Saturday walk through the woods to decompress from a stressful work week. They love their summer strolls, where they encounter all sorts of vegetation, animals and sounds of nature. John sbares that several days after their last walk he noticed a tick embedded in the skin of his upper thigh. The body of the tick was swollen. He was able to pull the tick out with tweezers and discard it in the toilet. He later developed a rash on his skin that looked like someone had painted a target on him. Kara notes that she also developed a weird target-like rash in her armpit several days after their walk. She doesn’t recall having any ticks attached to her; however, she admits to not performing any tick checks.
John and Kara both present with symptoms suggestive of possible Lyme disease from a deer tick (Ixodes scapularis) bite. While transmission of the infection occurs from a tick bite, many people never recall having the ectoparasite attached to them, which can likely be attributed to a tick’s small size and preference to attach themselves in less visible areas. Keeping John and Kara’s story in mind, let’s dive into Lyme disease and learn more about what you should do if there is concern about a possible infection.
Epidemiology
Lyme disease is the name given to the infectious syndrome caused by Borrelia burgdorferi infections. Borrelia burgdorferi is a helical shaped bacteria that is harbored in deer ticks and transmitted to humans during tick bites. Ticks acquire the bacteria from feeding on other small mammals and subsequently pass it to humans later in their life cycle.
Lyme disease is seen in areas where there are larger deer tick populations, which include the Northeast, mid-Atlantic, and upper Midwest. Of the countless tickborne infections, Lyme disease is the most common in the United States.
Transmission
Infections occur when nymphal or adult ticks attach/embed themselves in your skin. Generally, transmission of infection occurs after the tick has been attached for 36-72 hours, as this is the amount of time it takes for the bacteria to move from the tick’s gut into the saliva that is being secreted into your skin. The likelihood of infection transmission increases the longer the tick is attached.
In general, if the tick’s body looks swollen from its blood meal, it’s likely that it was attached long enough for infection transmission to have occurred. If the tick is merely crawling on your body and its body is not swollen, it is likely that it has not had its blood meal yet and therefore likelihood of infection transmission is low.
Testing
Testing for Lyme disease can be quite difficult. The diagnosis is commonly made clinically based on history and symptoms. There are blood tests available to check for antibodies to suggest a recent infection; however, these do not typically become accurate until 4-6 weeks after the tick bite occurred. If blood testing occurs, then it’s recommended to utilize an FDA-cleared antibody test. If testing is positive, the antibodies detected can persist for months to years even though no more bacteria are present. Subsequent exposures and decisions about new infection should be discussed with a healthcare provider.
Syndromes
The symptoms of untreated Lyme disease can be quite variable depending on the timing of infection and whether the infection has spread to other parts of the body.
Early localized infection
Symptoms of Lyme disease that occur within the first few weeks of a tick bite can include:
These symptoms generally occur between 3-30 days after the tick bite. A rash at the site of the tick bite (erythema migrans) occurs in approximately 70-80% of infected people. Treatment is generally with an oral antibiotic called doxycycline for a few weeks.
Disseminated and late Lyme (more than 30 days from bite) infection
The infection can sometimes spread to parts of the body beyond the skin and can be quite serious. Consequences of more serious infection include:
- Meningitis
- Facial palsy (loss of muscle tone in the face leading to facial droop)
- Arthritis (joint swelling and pain in weight-bearing joints – knees are the most common site)
- Irregular heart rhythm
- Myocarditis (inflammation of the heart muscle)
- Severe nerve pain
Depending on the type of infectious complication experienced, treatment can either be with IV antibiotics or oral doxycycline, depending on the infectious complication.
Post-Lyme syndrome
Unfortunately, following treatment for Lyme disease, it’s possible to develop a post-Lyme treatment syndrome characterized by fatigue, pain and/or cognitive impairment. This affects a minority of patients and can have negative impacts on quality of life. While the infection is gone, some of the consequences of immune dysregulation can still linger and cause symptoms. This syndrome continues to be an active area of research.
John and Kara both visited their primary care physician for further evaluation. Given John’s history of removing an engorged tick and developing an erythema migrans rash, he was diagnosed with early localized Lyme disease and treated with doxycycline. Within a few days, he began to see symptom improvement. Kara was also diagnosed with early localized Lyme disease given her characteristic rash and history of walking in the woods where she was at high risk for tick exposure. Despite not finding a tick attached to her, it was determined that she was also likely infected, as many people never identify a tick attached to them. She was also treated with doxycycline and within a few days began to see symptom improvement.
What we can learn from John and Kara, is that if you have concerns of a possible tickborne infection, be sure to schedule an appointment with your primary care physician for further evaluation. Early intervention can yield the best outcomes.
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