Does a Tick Bite Necessarily Mean You’ll Get Lyme Disease?

It’s officially tick season. Here’s how to spot the signs of infection, plus tips to prevent bites.

Does a Tick Bite Necessarily Mean You’ll Get Lyme Disease?

In the 1970s children in the area around Lyme, Connecticut began to develop odd unexplained symptoms—swollen knees, paralysis, skin rashes, headaches and severe chronic fatigue—while playing in the woods. The problems tended to show up after blacklegged ticks, also called deer ticks, bit them.

The source of the symptoms remained unclear until, in 1982, medical entomologist Wilhelm "Willy" Burgdorfer, PhD, and his coauthors published their finding that a corkscrew-shaped bacterium carried by deer ticks caused the condition Lyme disease.

These deer ticks are about the size of a poppy seed when they are still young, during the spring and summer, and most likely to cause an infection. “They’re very small and very hard to see,” explains Reid Blackwelder, MD, a professor of family medicine at East Tennessee State University in Johnson City.

A tick bit me, now what?
After being bitten by a tick you might notice a small bump or redness at the site, much like you’d see if a mosquito had bitten you. However, just because you have this rash from a tick bite doesn’t mean you’ll necessarily contract Lyme disease.

“People think that every tick has Lyme disease. But the infected ticks are only in certain places,” Blackwelder says.

Nearly all U.S. cases of Lyme have come from bites in one of these fourteen states—Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia and Wisconsin.

And even in locations where Lyme disease is common, only half of all ticks carry the disease, according to the American Lyme Disease Foundation.  

You might suspect Lyme if you live in an area with infected ticks and the symptoms occur during tick season, from mid-April to mid-September or October, Blackwelder advises. 

So if a bite doesn’t always mean Lyme—then what does signal the disease?

The telltale sign of Lyme disease
The most obvious sign of Lyme is a bulls-eye rash known as the “erythema migrans” rash. It doesn’t show up immediately after a bite. Instead, it appears in three to 30 days—but typically after seven days, on average, according to the Centers for Disease Control and Prevention (CDC). It can expand to up to 12 inches across, and as it enlarges it often has a clear area in the center, creating a “bull’s-eye” appearance.

Generally, if a physician sees the classic bulls-eye rash, you’ll receive a course of antibiotics for 10 to 21 days.

However, in 20 to 30 percent of Lyme cases, you won’t see any rash, according to the CDC. Scientists don’t know why some people get the rash and others don’t, Blackwelder says.

Other than the bull’s-eye rash, the early symptoms of Lyme aren’t distinctive. You might feel like you have the flu, experiencing symptoms like fever, chills, headache, fatigue or muscle and joint pain. However, any of those symptoms can come from other infections, including viruses, Blackwelder says.

So, what if a tick bites you, but you don’t see a rash and you don’t experience any other symptoms?

“Relax—you can probably forget about your tick bite,” Blackwelder says. If you were bit by a tick and didn’t get a rash but had flu-like symptoms that went away—then you probably don’t need to worry either. You may have had a bout of the flu or allergies, says Blackhelder.

Experiencing symptoms? See your doctor
If you are experiencing classic Lyme symptoms like the bull’s-eye rash, flu-like symptoms like fever, chills and headaches—don’t put off seeing your doctor. As time goes on, untreated Lyme disease can spread to the nervous system. If the condition does spread, then you might develop dizziness, numbing or tingling in the hands and feet, short-term memory problems, and a facial droop, the American Lyme Disease Foundation notes.

At that point, which can occur months or years later, you may need to receive intravenous, or through the vein, antibiotics. “It’s still curable in a later stage, but there may be damage that doesn’t go away,” Blackwelder adds.

Some people do not test positive for Lyme but because they have ongoing symptoms believe they have “chronic Lyme disease” that doesn’t show up on tests.  

“If all the lab tests are negative for Lyme disease, I would be thinking of some other disease or process. It could be another infection including ones caused by viruses; other immune conditions, or even something like multiple sclerosis. Basically, at this point, you need to see a doctor and sit down and figure it out,” Blackwelder adds.

8 ways to prevent tick bites
You can avoid tick bites by taking a few precautionary measures. Here’s how the CDC says to keep yourself safe from ticks all year long—but especially during warmer months when ticks are more active:

  • When walking or hiking, avoid high grass or brush areas, or areas with leaf litter.
  • Walk in the center of the trails; avoid the edges of the trail.
  • Wear long-sleeved shirts and pants, and tuck pants into shoes and socks.
  • Don’t go barefoot or wear open-toed shoes on trails or in woody, grassy areas.
  • Pick a spray repellent that contains at least 20 percent DEET, picaridin or IR3535 (always read and follow application instructions).
  • Take a bath or shower within two hours after being outside. This’ll help you possibly find and remove ticks.
  • Do a full-body tick check (under the arms, around ears, backs of knees, between legs and around the waist, as well as around the hair and scalp) after being outside in tick-populated areas. Parents should check their kids for ticks, too.
  • Check gear like bags and jackets, as well as pets for ticks.

The bottom line: If you get bit by a tick and aren’t feeling well after about a month, go and see a doctor. They can explore your medical history, conduct a physical exam and consider if the lab test is a correct step, advises Blackwelder.

Medically reviewed in May 2018.

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