STARI vs Lyme Disease: How to Tell the Difference After a Tick Bite
STARI can occur in the Northeast
Its rash can look like Lyme disease
The cause of STARI remains uncertain
STARI vs Lyme disease can be difficult to distinguish after a tick bite. Both conditions may cause an expanding erythema migrans-like rash along with fever, fatigue, headache, and muscle aches.
A 2026 report from Long Island, New York, highlights why this distinction is becoming increasingly difficult. An 8-year-old girl developed an expanding rash and systemic symptoms after a documented lone star tick bite. Investigators detected Borrelia lonestari in the tick, but the child herself was not tested for the organism.1
The case is important because lone star ticks are increasingly encountered in areas of the Northeast where Lyme disease is already common. Geography alone may therefore be less helpful than it once was in distinguishing STARI from Lyme disease.
In clinical practice, I have also seen patients in the southern United States diagnosed with STARI who were not informed that Lyme disease could still be a possibility.
As tick populations expand and overlap geographically, the diagnosis should consider the tick species, exposure history, rash, symptoms, laboratory findings, and clinical course rather than relying on location alone.
What Is STARI?
Southern Tick-Associated Rash Illness (STARI) is a Lyme-like illness associated with the bite of the lone star tick (Amblyomma americanum).
STARI is characterized primarily by an expanding red rash around the site of a lone star tick bite. Patients may also experience fever, headache, fatigue, muscle aches, and joint pain.2,4
The cause remains unknown. There is currently no diagnostic blood test that can confirm STARI.4
STARI is also not known to be caused by Borrelia burgdorferi, the bacterium responsible for Lyme disease. Lone star ticks have not been established as vectors of B. burgdorferi.4
STARI Symptoms
STARI symptoms may resemble early Lyme disease and can include:
- Expanding red or target-like rash
- Fever
- Headache
- Fatigue
- Muscle aches
- Joint pain
- Malaise
The similarity matters because the rash alone may not immediately distinguish STARI from erythema migrans caused by Lyme disease.
A Child With STARI in New York
A 2026 report in the CDC journal Emerging Infectious Diseases illustrates how STARI can now create a diagnostic challenge even in a Lyme-endemic region.1
An 8-year-old girl living on eastern Long Island developed a 5-cm annular lesion with peripheral redness and a central nodule on her upper back. She also experienced:
- Low-grade fever
- Posterior cervical lymphadenopathy
- Myalgia
A tick had been removed from the same area 12 days before the rash appeared and, importantly, the tick had been saved.1
Because early localized Lyme disease was initially suspected, the child’s pediatrician prescribed a two-week course of amoxicillin. Her rash and associated symptoms resolved within one week.1
However, subsequent identification of the tick changed the interpretation of the illness.
The tick was an adult male lone star tick, Amblyomma americanum, rather than the blacklegged tick associated with Lyme disease.1
Why Was Borrelia lonestari Found in the Tick?
Investigators tested the lone star tick and detected DNA from Borrelia lonestari.1
This finding is intriguing because B. lonestari has been investigated for years as a possible cause of STARI.
However, finding B. lonestari in the tick does not establish that it caused the child’s illness.
The child herself was not tested for B. lonestari. The authors therefore could not determine whether the bacterium was transmitted or whether it was responsible for her symptoms.1
This distinction is important because previous studies have not consistently detected B. lonestari in patients diagnosed with STARI.
A 2025 study evaluated 58 patients with STARI and used 16S sequencing to look for bacterial organisms. Investigators did not identify a known bacterial pathogen in those patients.3
CDC therefore continues to describe the cause of STARI as unknown.4
Does Borrelia lonestari Cause STARI?
We still do not know.
Early reports raised the possibility that B. lonestari might cause STARI. However, subsequent investigations failed to consistently detect the organism in patients with the illness.1,3,4
Other explanations have also been proposed, including the possibility that some cases reflect an inflammatory or hypersensitivity response to a lone star tick bite rather than infection with a specific bacterial pathogen.1
The 2026 Long Island case renews interest in B. lonestari because the organism was identified in the tick that bit the child. But it does not settle the question.
The most accurate conclusion remains that STARI is associated with lone star tick bites, while its underlying cause has not been established.
Why Is STARI Becoming More Important in the Northeast?
STARI was historically discussed primarily as an illness of the southern and south-central United States.
That geographic distinction is becoming less reliable.
Lone star ticks are now widely distributed in portions of the Northeast, including areas where blacklegged ticks and Lyme disease are also common.1,4
The 2026 authors emphasized that increasing lone star tick populations on Long Island make it more difficult to determine whether an erythema migrans-like lesion represents Lyme disease or STARI.1
This means that a Lyme-like rash in New York or another northeastern state can no longer automatically be interpreted based solely on geography.
For a broader discussion of diseases and conditions associated with this tick, see Lone Star Tick Bite: More Than One Kind of Illness?
Why Saving the Tick Mattered in This Case
The Long Island case also demonstrates why identifying the tick can sometimes provide clinically useful information.
The child had an expanding rash in a Lyme-endemic area. Without the saved tick, early Lyme disease would have been a reasonable consideration.
Because the family preserved the tick, investigators were able to identify it as a lone star tick.1
Tick identification does not diagnose the patient. A positive pathogen result from a tick also does not prove that transmission occurred.
But knowing the species can substantially change the differential diagnosis because different tick species are associated with different illnesses.
Learn more in Why Does Identifying the Tick Matter After a Bite?
STARI and Lyme Disease: Similarities and Differences
STARI and Lyme disease can both produce an expanding erythematous lesion after a tick bite. Constitutional symptoms such as fever, fatigue, headache, and muscle aches may also overlap.
Research comparing patients with Lyme disease in New York with patients presumed to have STARI in Missouri has suggested several possible differences.
Patients presumed to have STARI tended to develop their lesions sooner after the tick bite and had lesions that were smaller, more circular, and more likely to show central clearing. They also tended to report fewer systemic symptoms and recovered more quickly.1
These are group-level observations, however. They do not provide a definitive bedside test capable of distinguishing every individual case.
The tick species can therefore become an important additional clue when it is available.
A Florida Case Also Demonstrated the Overlap
An earlier case report described a 63-year-old woman who developed fever, headache, diffuse muscle pain, and a target-like rash after a lone star tick bite while camping in Gainesville, Florida.2
Laboratory abnormalities included leukopenia, anemia, thrombocytopenia, and elevated liver enzymes.
Testing for Lyme disease, ehrlichiosis, and anaplasmosis was negative. She was treated with doxycycline for 14 days and improved.2
The case illustrated how closely STARI can resemble other tick-borne illnesses and why the diagnosis may remain uncertain when no definitive laboratory test is available.
Could Some Patients Diagnosed With STARI Actually Have Lyme Disease?
This remains an important clinical question, particularly when the tick was never recovered or identified.
In my practice, I have cared for patients with persistent fatigue, pain, cognitive difficulties, or neurologic symptoms who were initially told they had STARI and reassured that long-term complications were unlikely.
Some later improved with treatment approaches commonly used for Lyme disease and associated tick-borne infections.
These clinical observations do not establish that STARI and Lyme disease are the same illness. They do highlight the importance of reconsidering the diagnosis when the clinical course does not unfold as expected.
Unlike Lyme disease, STARI still lacks:
- A confirmed causative organism
- A validated diagnostic blood test
- Well-established treatment guidelines
- Extensive long-term outcome data
When symptoms persist or evolve, clinicians should remain open to Lyme disease, another tick-borne infection, or an unrelated diagnosis rather than assuming that the initial label necessarily explains the entire illness.
What Does the 2025 STARI Study Add?
A 2025 study provides more recent information about STARI than many of the older case reports.3
Researchers evaluated 58 patients diagnosed with STARI during 2018–2019. Using 16S sequencing, they were unable to identify a known bacterial pathogen.3
The study also documented considerable variation in rash appearance and clinical presentation.
Patients who received antibiotics had a shorter duration of rash in the overall analysis, although this type of observational finding cannot establish that antibiotics were responsible for the difference.3
The study reinforces two important points: STARI is a recognizable clinical syndrome, but its cause and optimal treatment remain unresolved.
How Is STARI Treated?
There is no established antibiotic treatment regimen specifically proven for STARI.
CDC states that it is unknown whether antibiotics are necessary or beneficial for STARI, although clinicians sometimes prescribe oral antibiotics because the illness resembles early Lyme disease.4
The 2026 authors highlighted the practical difficulty this creates in Lyme-endemic areas. Withholding antibiotics when STARI is suspected could risk undertreating a patient who actually has Lyme disease if the tick species or diagnosis is uncertain.1
The New York child received amoxicillin because early Lyme disease was initially suspected and improved within a week. However, her improvement cannot establish that the antibiotic treated STARI because the natural course of the illness and the effect of antibiotic therapy cannot be separated in an individual case.1
Can STARI Cause Long-Term Problems?
Long-term complications have not been well documented in STARI, but the evidence base remains much smaller than it is for Lyme disease.
The 2026 report describes STARI as generally self-limited and notes that recognized sequelae after rash resolution have not been established.1
However, limited evidence should not be interpreted as proof that every patient follows the same course.
If symptoms persist, recur, or evolve after a presumed case of STARI, the diagnosis deserves reconsideration rather than assuming that all subsequent symptoms must be explained by STARI.
How Long Does STARI Last?
Many reported patients improve relatively quickly, but the natural history of STARI has not been fully characterized.
Rash duration and systemic symptoms vary, and many published patients have also received antibiotics, making it difficult to separate the untreated natural history of STARI from treatment effects.1,3
Why This Matters Clinically
The changing geography of the lone star tick creates a new diagnostic problem.
For years, geography provided a relatively simple clue: Lyme disease was strongly associated with the Northeast and Upper Midwest, while STARI was discussed primarily in the South.
That distinction is becoming less dependable.
When lone star ticks and blacklegged ticks occupy the same region, an expanding rash after a tick bite requires more clinical reasoning than geography alone can provide.
The 2026 Long Island case demonstrates the value of considering:
- The species of tick, when known
- Where the exposure occurred
- The timing and appearance of the rash
- Associated symptoms
- Appropriate laboratory testing
- The subsequent clinical course
This broader approach can help reduce both missed Lyme disease and inappropriate certainty about STARI.
Learn more about delayed Lyme disease diagnosis.
Questions Addressed in This Podcast
- What is STARI?
- Are there differences between STARI and Lyme disease rashes?
- Are different ticks associated with STARI and Lyme disease?
- How is STARI diagnosed compared with Lyme disease?
- What clinical evidence is used when there is no STARI blood test?
- What are the consequences if Lyme disease or another tick-borne infection is overlooked?
- How does geography affect the diagnosis?
WATCH PODCAST BELOW
CLICK BELOW TO LISTEN TO PODCAST
Frequently Asked Questions
What is STARI?
STARI, or Southern Tick-Associated Rash Illness, is a Lyme-like illness associated with the bite of the lone star tick. It commonly produces an expanding red rash and may also cause fever, headache, fatigue, and muscle or joint pain.
What causes STARI?
The cause remains unknown. Borrelia lonestari has been investigated as a possible cause, but studies have not established that it is responsible for STARI.
Does Borrelia lonestari cause STARI?
It has not been proven. A 2026 New York case found B. lonestari in the lone star tick removed from a child with STARI, but the child was not tested for the organism. The finding therefore does not establish causation.
What are the symptoms of STARI?
Symptoms may include an expanding red or target-like rash, fever, headache, fatigue, muscle aches, joint pain, and malaise following a lone star tick bite.
How is STARI different from Lyme disease?
Both can produce an erythema migrans-like rash and similar systemic symptoms. Lyme disease is caused by Borrelia burgdorferi and is transmitted by blacklegged ticks. STARI is associated with lone star ticks, and its cause remains unknown.
How is STARI diagnosed?
There is no validated blood test for STARI. Diagnosis relies on the clinical presentation, exposure history, geography, and—when available—identification of the tick.
How is STARI treated?
Some clinicians prescribe antibiotics because STARI closely resembles early Lyme disease, but it has not been established whether antibiotics are necessary or beneficial for confirmed STARI.
Can STARI cause long-term problems?
Long-term complications have not been well established. Published evidence remains limited, so persistent or evolving symptoms warrant continued clinical evaluation.
Can Lyme disease occur in the South?
Yes. Geography alone should not be used to exclude Lyme disease, particularly when the exposure history and clinical presentation are compatible.
Can STARI occur in New York?
Yes. A 2026 report described STARI in an 8-year-old girl on eastern Long Island after a documented lone star tick bite.
Can STARI occur in the Northeast?
Yes. Lone star ticks are now widely distributed in parts of the Northeast. As lone star ticks and blacklegged ticks increasingly overlap geographically, location alone may not reliably distinguish STARI from Lyme disease.
Should I save the tick after a tick bite?
If practical, saving the tick or taking clear photographs may help with later species identification. Identifying a tick does not diagnose an infection, but it can provide useful information about which tick-borne illnesses should be considered.
Clinical Takeaway
STARI and Lyme disease can appear remarkably similar, and the expanding range of lone star ticks is making geography less useful for distinguishing between them.
The 2026 Long Island case is particularly important because an 8-year-old child developed an erythema migrans-like rash and systemic symptoms after a documented lone star tick bite in a region where Lyme disease is common.
Borrelia lonestari was detected in the tick, but not demonstrated in the child. The finding is scientifically interesting but does not establish that B. lonestari causes STARI.
When possible, identifying the tick can provide valuable clinical context. But the diagnosis should still consider the entire picture—including the rash, symptoms, exposure history, laboratory findings, and clinical course.
An expanding Lyme-like rash in the Northeast should not automatically be attributed to either Lyme disease or STARI based on geography alone.
Related Articles:
Lone Star Tick Bite: More Than One Kind of Illness?
Why Does Identifying the Tick Matter After a Bite?
References:
- Handel, A. S., Ahmed, S., Rochlin, I., & Kim, H. K. (2026). Southern tick–associated rash illness in pediatric patient, New York, USA, 2025. Emerging Infectious Diseases, 32(9), 1508–1510. https://doi.org/10.3201/eid3209.260871
- Abdelmaseih, R., Ashraf, B., Abdelmasih, R., Dunn, S., & Nasser, H. (2021). Southern tick-associated rash illness: Florida’s Lyme disease variant. Cureus, 13(5), e15306. https://doi.org/10.7759/cureus.15306
- Lindell, K., Sheldon, S., Kingry, L., Mead, P. S., Molins, C., & Hinckley, A. F. (2025). Epidemiologic and clinical characteristics and outcomes of patients diagnosed with Southern Tick Associated Rash Illness (STARI)—2018–2019. Diagnostic Microbiology and Infectious Disease, 113(2), 116928. https://doi.org/10.1016/j.diagmicrobio.2025.116928
- Centers for Disease Control and Prevention. (2026, March 24). About Southern Tick-Associated Rash Illness.
This article is for educational purposes and is not a substitute for individualized medical evaluation or treatment.
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
Emerging? I had multiple tick bites as a child during summer trips to Kentucky, in the early to mid 1970s.
I has taken a while for doctors and researchers to document ticks and tick borne diseases in new areas. Until someone writes it up, the typical answer might be we don’t have tick or we don’t have tick borne diseases in this area.
I have been ill since the spring of 1987 . I lived in a wooded area near a lake . I saw several Possums and Raccoons when I lived there . I had not lived there long and I was clearing brush and taking it into the woods . When I finished and was cleaning up . I found a Tick embedded in my left arm . I removed it with tweezers and flushed it .It wasn’t long before subtle changes began .Visual problems ,fatique and and a strange sensation in my left foot and left arm . Several months later I was diagnosed with Hemianopsia . I started having memory problems .Nobody seemed to know what was wrong . It wasn’t until 1999 and my mother was watching a show about Lyme Disease and she called me to tell me how the rash shown on the show looked the same as the one I developed after the Tick bite .I contacted a Infectious disease Doctor and he did treat me with iv antibiotics . I did get better after being bed ridden and having to use a walker while undergoing