The chances that you might get Lyme disease from a single tick bite depend on the type of tick, where you acquired it, and how long it was attached to you. Many types of ticks bite people in the U.S., but only blacklegged ticks transmit the bacteria that cause Lyme disease. Furthermore, only blacklegged ticks in the highly endemic areas of the northeastern and north central U.S. are commonly infected. Finally, blacklegged ticks need to be attached for at least 24 hours before they can transmit Lyme disease. This is why it’s so important to remove them promptly and to check your body daily for ticks if you live in an endemic area (and we do).
It’s important to know and watch for symptoms of Lyme disease because ticks are hard to find and it’s easy to overlook a tick bite — in fact, many people who get Lyme disease don’t remember being bitten. The good news is that most tick bites don’t result in Lyme disease.
The signs and symptoms of Lyme disease are variable, usually involving more than one system. The skin, joints and nervous system are affected most often. In general, Lyme disease can cause:
- Rash. A few days to a month before you have other symptoms, a small, red bump may appear at the site of the tick bite. Over the next few days, the redness expands, forming a rash in a bull’s-eye pattern, with a red outer ring surrounding a clear area. The rash, called erythema migrans, is one of the hallmarks of Lyme disease. Some people develop several of these rashes, an indication of bacteria multiplying in the blood stream.
- Flu-like symptoms. Fever, chills, fatigue, body aches and a headache may accompany the rash.
- Migratory joint pain. If the infection is not treated, you may develop bouts of severe joint pain and swelling several weeks to months after you’re infected. Your knees are especially likely to be affected, but the pain can shift from one joint to another.
- Neurological problems. In some cases, inflammation of the membranes surrounding your brain (meningitis), temporary paralysis of one side of your face (Bell’s palsy), numbness or weakness in your limbs, and impaired muscle movement may occur weeks, months or even years after an untreated infection.
- Less common signs and symptoms. Some people may experience heart problems — such as an irregular heartbeat — several weeks after infection, but this rarely lasts more than a few days or weeks. Eye inflammation, hepatitis and severe fatigue are possible as well.
When to see a doctor
If you know you’ve been bitten and experience signs and symptoms of Lyme disease — particularly if you live in an area where Lyme disease is prevalent — contact your doctor immediately. Treatment for Lyme disease is most effective if begun early. Only a minority of deer tick bites leads to Lyme disease. The longer the tick remains attached to your skin, the greater your risk of getting the disease.