What Does a Lyme Disease Rash Look Like? Symptoms and EM Rash Variations
Lyme disease rashes do not always look like a bull’s-eye
EM rashes vary by color, shape, and location
Recognizing these differences may reduce delays in diagnosis
Welcome to another Inside Lyme Podcast. I am your host Dr. Daniel Cameron. In this episode, I discuss a question I am asked frequently: what does a Lyme disease rash look like?
Many patients expect a classic bull’s-eye rash, but erythema migrans (EM) rashes vary considerably. Differences in color, size, shape, and location may complicate diagnosis.
The study by Rebman and colleagues entitled “The presenting characteristics of erythema migrans vary by age, sex, duration, and body location” addressed an important question: what does a Lyme disease rash look like?
The erythema migrans rash is often considered the hallmark rash of Lyme disease. However, relying only on a classic bull’s-eye appearance may delay recognition and treatment.
What Does an Erythema Migrans Rash Look Like?
The authors examined 271 Lyme disease patients who had an erythema migrans rash to determine what does a Lyme disease rash look like?
“We studied associations between these presenting characteristics [of EM rashes], as well as whether they were associated with age, sex, EM duration, body location, and initiation of antibiotics,” the authors write.
The patients were part of a longitudinal cohort study from 3 sites in Maryland and southeastern Pennsylvania. They were not enrolled if their rash was under 5 cm in diameter (2 inches) or their acute illness was longer than 3 months.
These findings reinforce why Lyme disease remains largely a clinical diagnosis discussed further in Why Lyme Tests Medicine.
The study found that:
- EM size increased over time with the EM duration peaking at 14 days.
- Males had larger rashes than females (an average of 2.8 cm larger).
- Males were more likely to have a blue/red rash. In fact, the odds of a red rash in males was 65% lower than in females.
- Age was a significant predictor of central clearing. For every 10-year increase in age, the odds of central clearing decreased 25%. As age increased, there was a greater likelihood of a solid rash.
- EM rashes were more likely to occur in harder to see body locations (i.e., behind the thigh and behind the knees). The authors assumed that ticks had an opportunity to attach longer in these areas before being discovered.
- Nearly 1 in 3 patients had multiple rashes on examination.
- Approximately 1 in 3 patients reported pain at the site of the rash.
- Just over 50% of the EM rashes were itchy.
- Rash shapes were varied ─ 50.9% were round; 39.1% were oval. The remaining rashes were irregular.
- Rash colors were varied ─ about 3 out of 4 were red. The remaining rashes were blue/red.
- Rash patterns were varied ─ only 28% appeared as a Bull’s-eye rash (a ring within the rash). Central lightness (17.3%), central darkness (28.8%) and uniform rashes (25.8%) were also described.
- Over 90% of the rashes were homogeneous. The remaining rashes were uneven.
- Nearly 9% presented with vesicles.
Do All Lyme Disease Rashes Look Like a Bull’s-Eye?
No. Only a minority of erythema migrans rashes appear as the classic bull’s-eye pattern.
The study found substantial variation in rash appearance. Many patients had solid lesions, irregular shapes, central darkness, or central lightening rather than the classic target lesion.
These differences may explain why Lyme disease rashes are frequently missed or mistaken for other conditions.
Additional examples can be found at Lyme rash misdiagnosis and bull’s-eye confusion.
Can a Lyme Disease Rash Itch?
Yes. Lyme disease rashes can itch.
More than half of the erythema migrans rashes in this study were itchy, while approximately one-third were painful.
These symptoms may lead clinicians and patients to mistake Lyme disease for allergic reactions, fungal infections, insect bites, or eczema.
Where Are Lyme Disease Rashes Usually Found?
Rashes commonly appear in locations that are easy to overlook.
- Behind knees
- Behind thighs
- Groin areas
- Back
- Hair-bearing areas
Hard-to-see locations may increase the risk of delayed recognition. Prevention strategies are discussed further in prevention of Lyme disease.
Concerns With Limiting Size of Lyme Disease Rash
The authors raised concerns with following a 5 cm (or less than 2 inches) cutoff for EM rashes in determining the presence of a Lyme disease infection.
“Applying a 5 cm size cutoff in research or surveillance settings may thus exclude a higher proportion of females with otherwise suggestive clinical histories and epidemiological risk,” the authors write.
They also raised concerns about recognizing an EM rash in darker skinned patients. “95.9% of our final sample self-identified as non-Hispanic white.”
The authors suggest that variation in EM rash presentations in males versus females and among various ages may be related to immune responses to Borrelia infection.
Why Rash Recognition Matters
Because erythema migrans remains a clinical diagnosis, recognizing variability in rash appearance is important.
Rash shape, color, location, itchiness, and size all vary considerably.
Recognition challenges contribute to delays discussed further in delayed Lyme disease diagnosis.
Editor’s Note
Unfortunately, fewer than half of Lyme disease patients present with an erythema migrans rash.
This case series reflects the diversity of rashes in Lyme disease patients fortunate enough to present with visible skin findings.
Patients without rashes may require symptom-based evaluation using broader frameworks such as the Lyme disease symptoms guide and careful clinical assessment with testing for Lyme disease.
Frequently Asked Questions
Does a Lyme disease rash always itch?
No. Some Lyme disease rashes itch while others do not.
Does a bull’s-eye rash always mean Lyme disease?
No. Several conditions can resemble a bull’s-eye rash although Lyme disease remains an important consideration.
What does an erythema migrans rash look like?
EM rashes vary in size, color, pattern, and shape. Many do not resemble textbook bull’s-eye images.
Can Lyme disease cause multiple rashes?
Yes. Nearly one-third of patients in this study had multiple lesions.
Can Lyme disease rashes be small?
Yes. Smaller rashes may still be clinically important.
Clinical Takeaway
Lyme disease rashes vary considerably in appearance and frequently differ from textbook examples.
Recognizing variability in rash color, shape, size, location, and itchiness may improve early diagnosis.
Relying solely on a classic bull’s-eye appearance may lead to delayed recognition and treatment.
Related Articles
These articles explore diagnosis, rash recognition, and symptom variability.
Persistent Lyme Disease Symptoms
Neurologic Lyme Disease
Recovery From Lyme Disease
Lyme Disease Misdiagnosis
Bad Signs After a Tick Bite
References
- Rebman AW, Yang T, Mihm EA, et al. The presenting characteristics of erythema migrans vary by age, sex, duration, and body location. Infection. 2021. doi:10.1007/s15010-021-01590-0
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
I live in Canada and was infected in France while I was visiting my daughter who lives there. The rash was an expanding oval rash. Didn’t look like a bullseye so I thought I was OK. When I saw a Lyme Doctor in the USA (Canada has none) she said any rash of any kind after a tick bite is a sign of trouble. I say that needs to be made public knowledge. I would have gone to a doctor in France or at least as soon as I came home if I had known.
For sure, I got bit in Traverse City MI on a family trip 4 yrs ago, in live in AZ and lyme does not exist here and was treated by doctors that said I had cellulitis and/or shingles, rash did not go away and went to thr ER and a bullseye was spotted at the ER and Dermatologist Office, I begged them and they finally put me on doxycycline for two months, it made the rash finally disappear but 3 years later I still get swelling in my one leg and ankle and pain and brain fog. I hope you were able to at least get on some sort of medication. My brother got bit by a tick in Michigan, he did not get lyme but another tick issue and after several doctors, he got one to put him on minocycline for two years. sorry about spelling. I wish you luck and that you are ok.
I have what looks like Erthema Migrans Rash. They keep telling me I test negative for Lyme. My speech is now effected and I was diagnosed last Sept with a tick borne illness that made me very sick. soon after that I developed red spots on both wrist with hard centers. Soon after that this happened on my left breast, left side of my belly and all around my groin. I am at wits end to figure out if this is due to Lyme, most doctors I’ve been to dismiss it when I bring it up. I live in Vt. and would like to see a Lyme specialist but insurance won’t cover it unless diagnosed. Anyone know the next step. They want to send me to a dermatologist and sleep study. I already have seen a neurologist and did not have stroke. I’m 61 and feeling crappy all the time. No energy ,wake up feeling tired. I seem to loose balance and sometimes trip easily. Hot Flashes, slurred speech and my brain does not work well in the afternoon.
You also need to write about the different rash you get in Europe (expanding oval rash from Borrelia garinii).
There are Canadians who have family in the UK, France and Germany and visit them once a year for a month.