What Is ​Lyme Disease?

This informational guide, part of POPSUGAR's Condition Center, lays out the realities of this health concern: what it is, what it can look like, and strategies that medical experts say are proven to help. You should always consult your doctor regarding matters pertaining to your health and before starting any course of medical treatment.

Being outdoors — picnicking in the park, hiking in the woods, and barbecuing in the backyard — is one of the true joys of spring and summer. The downside: deer ticks like those seasons, too. And a bite from one of the tiny bugs can transmit a number of different types of bacteria, including Borrelia burgdorferi, the species that causes Lyme disease. The condition usually causes mild symptoms, but in some, it can trigger health problems that last for years.

About 476,000 people are diagnosed with and treated for Lyme disease in the US every year, according to the Centers for Disease Control and Prevention. But climate change is allowing the ticks to spread into new areas like Canada, where the environment was previously inhospitable to the arachnids, so that number has been on the rise, the United States Environmental Protection Agency reports. As of 2018, the incidence of Lyme disease in the United States had nearly doubled since 1991, the EPA found.

Early symptoms of the condition are similar to the flu: fever, chills, headache, fatigue, muscle and joint achiness, and swollen lymph nodes. The sign that's long been considered a hallmark of the disease, a rash in the shape of a bullseye at the bite site, actually only appears in about 70 to 80 percent of people with Lyme, the CDC notes. And because the ticks themselves are minuscule — about the size of a poppy seed — people often don't realize they've been bitten and, as a result, may not connect any flu-like symptoms they eventually develop to a tick bite. In that case, they may not get the right treatment for months or even years.

"Untreated Lyme, or cases that don't respond to treatment, can cause long-term problems, including Lyme-related arthritis, when the bacteria enter joint tissue and cause inflammation, and post-treatment Lyme disease syndrome, which can cause fatigue, pain, and cognitive impairment long after treatment," says Brian Fallon, MD, director of the Lyme and Tick-Borne Diseases Research Center at Columbia University. Chronic symptoms occur in an estimated 10 to 20 percent of people who have been bitten by a tick, Dr. Fallon says.

A tick bite, usually from a deer tick, causes acute and chronic Lyme infections. But there are some added factors that may be associated with the development of long-term symptoms.

First, prevention: keep your skin covered when you're spending time outdoors, especially when you'll be around tall grass or wooded areas, where ticks like to hide out. Spray your clothes with an anti-tick product containing 0.5 percent permethrin. And check your clothing and skin for ticks when you come inside. The underarms, ears, belly button, backs of knees, hair, and between the legs are some of their favorite places to latch on.

If you spot a tick, remove it immediately (the CDC website has instructions on how). The earlier you remove ticks, the less likely you are to develop symptoms. Then, call your doctor. In some conditions, it may be appropriate for you to start a course of antibiotics ASAP, especially if you live in an area where Lyme is common. Even if your healthcare provider doesn't suggest prophylactic meds, you should watch for symptoms for 30 days. If you develop them, visit your doctor for testing and treatment. "We treat early cases with two to four weeks of antibiotics — usually doxycycline, which is quite effective," Dr. Fallon says.

Initial bouts of Lyme arthritis, which usually hit about one to three months after the infection, are treated with oral antibiotics as well, but if the joint inflammation and pain don't respond to the medication, doctors might prescribe intravenous antibiotics.

For those with symptoms of Post-Treatment Lyme Disease Syndrome (PTLDS), the treatment depends on the cause, which, in many cases, remains a mystery. Potential causes include persistent bacterial infection, which might respond to antibiotics; brain inflammation, which might be treated with drugs designed to minimize neuroinflammation; and changes in the gut microbiome, which could improve with dietary measures, according to Dr. Fallon.

"It's natural for people with long-term symptoms to feel a sense of despair and worry they'll never get better," Dr. Fallon says. "But the vast majority of people, even those who are very sick, do tend to improve, and even recover, with time."