What is Lyme Disease?

In the 1970s, there was an epidemic of arthritis, often preceded by a strange, expanding red rash, occurring primarily in children in and around Lyme, CT. The cause of this “Lyme arthritis” was a mystery until investigators discovered that these children had been infected with Borrelia burgdorferi, a spiral-shaped bacteria (spirochete) that had been transmitted to them via a tick bite. They also found that the disease caused more than just joint aches and a rash—it could affect many other organ systems including the heart and nervous system.

From an odd, local curiosity, Lyme disease has spread to become a worldwide scourge. In the US alone—especially in New England, the Mid-Atlantic states, Wisconsin, and Minnesota—approximately 30,000 cases are reported every year, although the actual incidence may be 10 times greater.

In “I’ve Been Bitten by a Tick! What Do I Do?” we talked about how to avoid tick bites and what to do if you’re bitten. Here, we take a deeper dive into the clinical manifestations of Lyme disease and its diagnosis and treatment.

With rare exceptions, a tick has to be attached to your body for at least 48 hours to infect you. Anywhere from three days to one month after the bite of an infected tick, a red rash will appear at the site. Often, it has a central clearing (so it resembles a bull’s-eye) and progressively enlarges, appearing to migrate across the skin. It’s usually painless and sometimes itchy.

The rash is usually accompanied by flu-like symptoms—fever, muscle and joint aches, headache, and fatigue. This is usually when Lyme disease is diagnosed and treatment begins. With or without treatment, the rash—called erythema migrans—will persist for several weeks and then disappear.

Without treatment, a few weeks after the bite, it’ll reach the second stage—disseminated Lyme disease. The infection spreads and many smaller erythema migrans rashes can appear anywhere on the body. The spirochete can also start causing other problems. Neurologic issues (most commonly Bell’s palsy, a partial paralysis of the face) and heart issues (typically heart block, a disruption in the heart’s electrical system that regulates heartbeat) are most common. Several weeks to months after the tick bite, patients may also develop frank arthritis, usually in one or both knees.

In the early stages your blood won’t yet test positive for Lyme antibodies, but your provider can usually make a clinical diagnosis. Several weeks after its onset, blood tests can help make the diagnosis. Antibiotics are highly effective in all its stages, but more advanced patients may require intravenous antibiotics and, especially in patients with neurologic involvement or arthritis, longer courses of therapy.

There’s no evidence—and investigators have looked—that patients who are treated, but continue to complain of symptoms such as fatigue and muscle aches, have ongoing, inadequately treated Lyme disease. Many of these patients have a second infection with the Lyme spirochete, while others may have contracted a second tick-borne illness such as babesiosis or anaplasmosis. No benefit has been associated with continuing to treat these patients with oral or intravenous antibiotics (antibiotics themselves can have significant and sometimes serious side effects). Fortunately, most patients without an established cause for their ongoing symptoms simply get better over time.

The bottom line: Early treatment can prevent dissemination and more serious consequences. Know the signs and symptoms of the disease as outlined above, and see your healthcare provider if you think you may have Lyme disease.