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With the growing awareness of Lyme disease, many worry they have the illness. To contract Lyme, a blacklegged tick must attach to you for roughly 1 to 2 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. And tick bites are most often painless.

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

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 went camping or hiking. (Blacklegged ticks that carry Lyme-causing bacteria are most often found in the forest.)

Early, Localized Lyme Disease Symptoms

The most telltale sign of Lyme is a rash (called erythema migrans), which occurs at the site of the tick bite. (Remember, that might be on a part of the body you can’t easily see.) 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 is usually 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.

“When a tick bites, it’s just like a regular insect bite,” says Rutul Dalal, MD, Infectious Diseases specialist, UPMC in North Central Pa. “It can be painless, or it can be itchy. You will see some redness around the area, which is typical of an insect bite. But then, after four or five days of the tick bite, if the rash does not go away, if there is a halo around it, if there’s a target lesion with central clearing and increasing redness around the border, it can be a sign of tick infection.”

The 20% to 30% of people who don’t develop a rash (of any shape) may notice other symptoms in the first month. These include chills, headache, low energy, sore muscles and joints, and swollen lymph nodes.

These initial symptoms and rash are the body’s first immune response to a foreign bacteria. This is why, beyond the typical rash, the symptoms are non-specific and can resemble any flu-like illness.

Symptoms of Untreated, Disseminated Lyme Disease

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

“It’s not the initial achy, painful joint and the rash which you’re worried about,” Dr. Dalal says. “It’s more about the long-term ramifications of not being treated.”

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 are 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.

In rare cases, some people will develop post-Lyme disease syndrome. This describes Lyme-like symptoms that occur six months after the disease itself has been successfully treated. While little is known about why post-Lyme disease occurs, 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.

Editor's Note: This article was originally published on September 13, 2021, and was last reviewed on August 17, 2022.