The problem with "classic" Lyme disease symptoms

One day, Wendy noticed a quarter-sized rash at the top of her thigh. By the next day, it had grown to the diameter of a half-dollar. But since the flat, red patch didn't resemble the bullseye rash Wendy had seen listed among Lyme disease symptoms, it didn't even occur to her she might have the infection.

Wendy was wrong. She was one of the nearly 500,000 Americans infected each year with Lyme disease, which spreads through tick bites (primarily from deer ticks) transmitting the bacterium Borrelia burgdorferi.

Most people with early stage Lyme disease symptoms do indeed show up with a rash (known medically as erythema migrans), a Harvard expert says. But it often lacks bull's-eye features - creating a mismatch in expectations that can delay diagnosis and treatment. What's more, the bullseye pattern may be less visible on darker skin.

"Lyme disease is a complex infection, so it has different symptoms at different stages," says rheumatologist Dr. Allen Steere, director of the Lyme Arthritis Program at Harvard-affiliated Massachusetts General Hospital. "In early disease, the most characteristic symptom is a skin rash at the site of a tick bite."

"It's often not so classic as the bullseye rash, so consequently, it can be confused with other things," adds Dr. Steere, who discovered Lyme disease in 1976 and is one of the world's foremost experts on the condition. "The most characteristic feature is that the rash expands slowly."

Other signs of Lyme disease

The media sometimes overstate the pervasiveness of a bullseye rash in hopes of simplifying Lyme disease detection for the public, Dr. Steere notes. But while that approach can be problematic, certain other symptoms tend to reliably show up, including

• headache
• neck pain
• joint and muscle aches
• fatigue or malaise.

Over all, you may feel like you have the flu. But another misconception is that fever is always present - which not the case for most adults with early Lyme disease, Dr. Steere says. "Fever is not common, except in children," he says.

Symptoms can vary

In reality, there's no single script for early-stage Lyme disease symptoms. Some people never develop a noticeable rash, for example, while others get only mild or vague clues that Lyme disease is the culprit.

Other early signs of Lyme disease can even differ by sex, with men experiencing more sleep difficulty and irritability, and women - particularly those before menopause - reporting more frequent nausea, vomiting, and heart palpitations, according to a study published online Feb. 7, 2026, by Clinical and Experimental Medicine.

The analysis underscored how Lyme disease symptoms don't look the same in everyone and adds underrecognized factors - sex and menopause status - to variables doctors should consider when diagnosing the condition, Dr. Steere says.

"Gastrointestinal symptoms are usually not due to Lyme disease, but all these patients had a red rash - that's how they were diagnosed," he says. "So if you have an enlarging skin rash and gastrointestinal symptoms and you're a premenopausal woman, well, Lyme disease can look like that."

Diagnostic tests

This symptom variability can also make Lyme disease more challenging to diagnose, Dr. Steere says. To start, your doctor will ask about symptoms and perform a complete physical exam. Blood tests are also commonly used, though they may be negative in the first few weeks after infection - and in some cases can be positive in someone who doesn't have the illness.

"Medical diagnosis can be challenging, and there is variation in how any disease, really, can show up. Lyme disease is no different," Dr. Steere says.

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