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With the growing awareness of Lyme disease, many worry they have the illness. To contract Lyme, a deer tick must attach to you for roughly one to two days. That’s how long it typically takes for the bacteria that causes Lyme disease to transfer into your blood.

However, not everyone who develops Lyme remembers a tick bite. Ticks are so small and can latch in hidden areas like the scalp or groin. Also, tick bites are often painless.

So, how would you know if you have Lyme disease? The signs and symptoms tend to follow a clear pattern.

What Is Lyme Disease?

“Lyme disease is an infection caused by the bite of a deer tick,” says Andrew Nowalk, MD, in a video from UPMC Children’s Hospital of Pittsburgh. Dr. Nowalk is a pediatric infectious diseases expert at UPMC Children’s.

“(The bite) transmits bacteria that gets into the human body and causes a very specific set of symptoms,” Dr. Nowalk adds.

Within a few days to one month after the tick bite, most people start to develop symptoms. If you don’t recall a bite, you might trace your symptoms to when you last went camping or hiking. (You often can find deer ticks that carry Lyme-causing bacteria in the forest.)

What Are the Symptoms of Lyme Disease?

The telltale sign of Lyme is a rash (called erythema migrans), which occurs at the site of the tick bite. The rash might be in a place you can’t easily see, like the back of your head or between your legs. This rash occurs in 70% to 80% of patients.

On average, the rash shows up one week after the tick bite. But it can appear as early as three days or as late as 30 days after the bite.

The rash may feel warm but usually is not itchy or painful. The red patch will expand over several days and can grow as big as 12 inches across. The “classic” Lyme rash eventually takes on a bull’s eye shape, with a red circle in the middle and an outer red ring.

Since the bull’s eye shape doesn’t always appear, watch out for any circular or oval rash that gradually expands.

About 20% to 30% of people won’t develop a rash. However, they may notice other symptoms in the first month, including:

• Chills.
• Extreme fatigue.
• Headache.
• Sore muscles and joints.
• Stiff neck.
• Swollen lymph nodes.

These initial symptoms and the rash are the body’s first immune response to any foreign bacteria. That’s why, other than the rash, the symptoms are nonspecific and can resemble any flu-like illness.

Pennsylvania is one of the highest-risk states for Lyme disease in the country. It had the second-most diagnosed Lyme disease cases in 2022, according to the Centers for Disease Control and Prevention (CDC).

Dr. Nowalk says that the number of Lyme cases has risen dramatically over time.

“We’re seeing an epidemic of cases that’s of concern to the CDC, the state health department, and certainly to (UPMC) Children’s Hospital,” Dr. Nowalk says.

What Are the Symptoms of Untreated Lyme Disease?

If left untreated, the bacteria will usually spread throughout the body in the weeks or months following the bite. This spread is known as disseminated Lyme or late Lyme disease. And it can lead to more serious symptoms.

The symptoms of disseminated Lyme are widespread, as the bacteria can affect multiple organs and systems in the body. A person with disseminated Lyme may notice additional rashes. These can occur anywhere in the body, not just at the initial bite.

Muscle and joint issues are also common in the later stages of untreated Lyme disease. Soreness or arthritis pain that comes and goes in the muscles and joints is common. Some may experience facial palsy, a weakness in the facial muscles that leads to drooping on one or both sides.

In disseminated or late Lyme disease, the bacteria can affect the heart, brain, and nervous system. People may experience heart palpitations, an irregular heartbeat, and shortness of breath.

Inflammation of the brain and spinal cord can occur. This can also lead to headaches and confusion, as well as numbness, tingling, and nerve pain.

The symptoms of disseminated Lyme disease can last for several months. The good news is that Lyme disease is treatable at any stage.

What is post-Lyme disease syndrome?

In rare cases, some people will develop post-Lyme disease syndrome. This syndrome is characterized by Lyme-like symptoms that occur six months after the disease itself has been successfully treated.

Little is known about why post-Lyme disease occurs. But some think it occurs when the immune system stays overactive even after the bacteria is gone. The symptoms of post-Lyme disease syndrome generally resolve on their own.

How Can Lyme Disease Be Prevented?

The most effective way to avoid Lyme disease is to prevent the bite of deer ticks.

Dr. Nowalk has some suggestions for preventing tick bites and the transmission of Lyme disease:

• Avoid being outside at sunrise and sunset.  “Lyme disease-carrying ticks tend to circulate and bite most frequently at certain times of day,” Dr. Nowalk says. “And, at dawn and at dusk, they are particularly active.”
• Check for ticks on yourself and your family after you’ve been outside for an extended period.
• Wear insect repellent. Dr. Nowalk recommends a simple insecticide that contains a 10% to 30% concentration of DEET. You can even spray insect repellant on your clothes to keep ticks away.
• Wear long sleeves and long pants outside when possible.

Editor's Note: This article was originally published on September 13, 2021, and was last reviewed on February 4, 2025.