A telling sign of Lyme disease is a red, circular or oval rash that expands over time like a bulls-eye. Doctors call it “erythema migrans.” But if you’re looking for a bulls-eye pattern and ignoring other types of skin rashes and lesions, you’re probably missing an important clue to your diagnosis. Surprise, surprise: relatively few Lyme rashes mimic the concentric circles of a dart board.
The classic target pattern represents just 20% of Lyme-related skin lesions in North America, notes John Aucott, MD, associate professor of medicine at Johns Hopkins University School of Medicine in Baltimore and director of the Johns Hopkins Lyme Disease Research Center.
“Eighty percent don’t look like that, and they constantly get misdiagnosed as spider or bug bites,” he tells Health.
The fact is that Lyme disease rash can present itself in different ways, according to the Bay Area Lyme Foundation. How it appears on your body may depend, in part, on how long you’ve had it and where it shows up on your body.
Generally, erythema migrans is circular, because it spreads centrifugally from the point of the tick bite, says Dr. Aucott. But it can be more oval or elongated in shape if, for instance, the tick took its blood meal in the groove of your groin.
Its appearance may also depend on your skin tone, Andrea Swei, PhD, an associate professor specializing in tick-borne diseases at San Francisco State University, tells Health. In fact, some research suggests that Lyme rashes may not always be obvious in darker-skinned individuals, which can lead to disparities in diagnosis and treatment.
Doctors also point out that it’s possible to have Lyme disease with no visible rash, or a rash that clears up on its own before you notice it.
What do the rashes of Lyme disease look like?
Uniformly red rash
Multiple red rashes
lyme-disease-rash at Lifespan in Providence, Rhode Island, tells Health. When this happens, it means bacteria are no longer isolated to the area of the skin where the tick bite occurred. The Centers for Disease Control and Prevention (CDC) describes these rashes as having “dusky centers.”
Red-blue or bluish lesions
Can Lyme disease rash itch?
If you develop a Lyme disease rash, you probably won’t be scratching your skin until it’s raw. Still, Lyme disease rashes can be slightly itchy, even mildly painful, says Dr. Aucott, but they don’t itch like a case of poison ivy.
Lyme rashes often feel warm to the touch as well. Your doctor may perform what’s called a “crossover test” to gauge whether the area feels warmer than the rest of your skin, says Dr. Johnson. Here’s what that involves: Let’s say the rash is behind one knee. You place one hand on the rash and your other hand in the same area of the unaffected knee, wait a few seconds, and then switch hands. If there’s a difference in temperature, you’ll notice it.
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