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4 Symptoms of Lyme Disease You Should Know

June 24, 2025

In New England, we wait all year for summer – beach days, BBQs and hikes in the woods. But it doesn’t take long for ticks to ruin the fun.

Spread through the bite of an infected deer tick, Lyme disease symptoms can show up within 36 to 48 hours of a bite. If left untreated, the infection can affect your skin, joints, heart and nervous system.

The best defense? Knowing what to look for. Patrick Cahill, MD, an infectious disease specialist with Hartford HealthCare Medical Group, shares four key symptoms to watch for.

1. A rash that looks like a bullseye.

Think you got bit by a tick? Set a calendar reminder, and keep an eye on the spot over the next few weeks.

To transmit Lyme, deer ticks usually need to be attached for more than 24 hours – often closer to 48.

One of the first signs of Lyme is a rash called erythema migrans, which usually appears 3 to 30 days after a bite. These rashes can vary in appearance but should be at least 5 cm (about 2 inches) in diameter to be considered Lyme-related.

“It often looks like a bullseye and spreads slowly, but it doesn’t have to be a perfect circle,” says Dr. Cahill. “Any red area that’s getting larger – especially if it feels warm but isn’t itchy or painful – should be checked out.”

> Related: 3 Ways To Prevent Lyme Disease During Tick Season

2. Flu-like symptoms.

Noticing a fever, chills, severe headache or muscle pain?

If you’ve been outdoors lately, tune into your symptoms.

“This may be early Lyme disease,” explains Dr. Cahill. “It’s when the infection starts spreading beyond the original bite. Other tick-borne illnesses can cause the same symptoms, and we evaluate them with a few simple lab tests.”

3. Joint pain or swelling.

Weeks – or even months – after a tick bite, Lyme disease can show up in your joints, most often the knees.

“While early Lyme disease can cause joint pain, it can also skip those symptoms and present as true arthritis, with significant pain and swelling in a single joint,” says Dr. Cahill.

In areas like the Northeast, Lyme disease should always be on the radar as a possible cause.

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4. Other health issues.

As Lyme disease spreads, it can start to affect your nervous system – and the symptoms can be surprising.

Call your doctor if you notice:

• Dizziness.
• Facial drooping. Please visit urgent care or the emergency department if you have any new neurological symptoms.
• Heart palpitations (a fluttering or skipping beat).
• Neck stiffness.
• Severe headaches.

> Related: 3 Things to Do If You Have a Tick

Stay safe this summer.

Spending time outside is one of the best parts of summer – so don’t let ticks take that away.

To lower your risk, Dr. Cahill recommends:

• Check your body and clothes for ticks after being outside.
• Toss your clothes in the dryer on high heat for 15–20 minutes to kill any ticks. This is also the perfect time to check your body for ticks under your clothes.
• Apply DEET-based repellent to exposed skin.
• Treat clothes and gear with permethrin. Once it dries, it’s safe to wear – and stays effective for 6 weeks or through 6 washes.
• Remove attached ticks with tweezers, gripping as close to the skin as possible.

“With a few simple precautions, you can enjoy the outdoors and stay safe,” says Dr. Cahill. “And if something feels off, don’t wait to speak up.”