Why Lyme Disease Causes Heat and Cold Intolerance
Many patients with Lyme disease describe something they never struggled with before: they suddenly cannot tolerate heat or cold.
Most of these patients have a normal measured body temperature. They may feel intensely hot, chilled, flushed, or sweaty without having a documented fever.
Lyme heat and cold intolerance may be associated with changes in autonomic regulation, sweating, skin circulation, or temperature sensation. Patients may walk into a warm room and suddenly feel flushed, dizzy, or exhausted. Others feel chilled indoors when everyone around them seems comfortable.
Some patients alternate between sweating and shivering even though their core temperature remains normal.
For more on autonomic symptoms in Lyme disease, see Autonomic Dysfunction in Lyme Disease.
Can Lyme Disease Cause Temperature Intolerance Without a Fever?
Yes. Patients may experience real heat or cold intolerance without an elevated temperature.
A thermometer measures core body temperature. It does not measure temperature perception, sweat-gland function, blood flow near the skin, or the autonomic nervous system’s response to environmental changes.
A true fever is more likely near the beginning of an acute infection or during another active illness. Persistent temperature intolerance is different: the patient feels abnormally hot or cold, but a thermometer does not document a fever.
Recording the actual temperature during an episode can help distinguish a true fever from temperature intolerance.
Understanding Lyme Heat and Cold Intolerance
Temperature control depends on communication among the brain, autonomic nerves, small sensory fibers, sweat glands, blood vessels, muscles, and immune system.
The hypothalamus helps coordinate this process, but Lyme-specific research has not established hypothalamic damage as a common explanation for temperature intolerance.
Small sensory fibers transmit information about heat and cold. Small autonomic fibers help control sweat glands and blood vessels near the skin.
Changes involving these systems could potentially make ordinary temperatures feel unusually intense without producing an abnormal core temperature.
What May Contribute to Heat and Cold Intolerance?
Several mechanisms may contribute to temperature intolerance in patients with Lyme disease:
- Autonomic dysfunction affecting circulation and sweating
- Small-fiber involvement affecting heat and cold sensation
- Changes in vascular tone and skin blood flow
- Altered sensory processing of temperature signals
- Associated post-infectious dysautonomia
These remain possible mechanisms rather than proven explanations for every patient. Direct research specifically measuring temperature intolerance in Lyme disease remains limited.
What Does the Small-Fiber Neuropathy Research Show?
Small nerve fibers have both sensory and autonomic functions. They transmit heat, cold, pain, and burning sensations while also helping regulate sweating and blood vessels.
Novak and colleagues evaluated 10 patients with post-treatment Lyme disease syndrome using skin biopsies and autonomic testing.
The researchers found:
- At least one abnormal skin biopsy in all 10 participants
- Reduced epidermal nerve fiber density in 9 participants
- Abnormal sweat-gland nerve fiber density in 5 participants
- Mild-to-moderate autonomic abnormalities
These findings suggest that small-fiber neuropathy may be associated with sensory and autonomic symptoms in some patients with persistent symptoms after Lyme disease.
However, this was a small, retrospective study, and it did not directly measure heat or cold intolerance. The study supports a possible biologic pathway but does not prove that small-fiber neuropathy explains temperature symptoms in every patient.
Heat Intolerance in Lyme Disease
Heat intolerance is often one of the first temperature-related changes patients notice.
A hot shower that once felt relaxing may suddenly cause dizziness or exhaustion. Warm weather becomes draining. Even stepping into a heated car may provoke an immediate sensation of overheating.
Heat may worsen:
- Fatigue
- Brain fog
- Dizziness
- Palpitations
- Weakness
- Exercise intolerance
Heat causes blood vessels near the skin to dilate. In a patient with autonomic or vascular instability, this can make it more difficult to maintain blood pressure and circulation while standing.
A patient may therefore feel overheated, dizzy, or profoundly weak even though the thermometer remains normal.
Cold Intolerance in Lyme Disease
Other patients feel unusually cold despite a normal room temperature and a normal measured body temperature.
Patients may describe:
- A deep internal chill
- Cold hands and feet
- Difficulty warming up
- Feeling chilled “to the bone”
- Feeling cold when everyone else is comfortable
Changes in skin circulation or temperature sensation could potentially contribute. However, thyroid disease, anemia, low body weight, medications, and other medical causes should also be considered.
Temperature Swings With a Normal Temperature
Some patients experience both heat and cold intolerance. They may feel overheated one moment and chilled the next while repeated thermometer readings remain normal.
These sensations may reflect instability involving sweating, blood flow near the skin, or sensory signaling rather than repeated episodes of fever.
The presence of additional autonomic symptoms—such as dizziness, palpitations, exercise intolerance, digestive problems, or abnormal sweating—may provide useful clinical context.
Other Symptoms That May Accompany Temperature Intolerance
Heat and cold intolerance rarely occur in isolation.
Associated symptoms may include:
- Night sweats
- Flushing
- Excessive or reduced sweating
- Palpitations
- Dizziness while standing
- Exercise intolerance
- Brain fog
- Fatigue
- Cold hands and feet
- Digestive motility problems
These symptoms may fluctuate together and worsen with heat, dehydration, standing, exertion, illness, or other physiologic stressors.
When Is It a True Fever?
A true fever is a documented elevation in core body temperature. Fever may occur near the beginning of Lyme disease, often with fatigue, headache, muscle aches, or other flu-like symptoms.
A new or recurrent measured fever should not automatically be classified as autonomic dysfunction. It may indicate:
- Lyme disease or another active infection
- A tick-borne co-infection
- A medication reaction
- An inflammatory condition
- Another medical illness
Patients who feel feverish should measure and record their temperature whenever possible.
Could Chills and Sweats Indicate Babesiosis?
Babesiosis should remain in the differential diagnosis when a patient with tick exposure develops a measured fever, chills, or recurrent sweats.
Babesiosis is caused by a parasite that infects red blood cells. Possible manifestations include:
- Fever
- Chills
- Sweats
- Fatigue and weakness
- Headache and body aches
- Hemolytic anemia
- Low platelet counts
These symptoms can overlap with Lyme disease. Symptoms alone cannot confirm babesiosis, and appropriate laboratory evaluation may be needed.
What Else Can Cause Temperature Intolerance?
Feeling unusually hot or cold with a normal temperature is not specific to Lyme disease.
Other possible contributors include:
- Thyroid disease
- Anemia or iron deficiency
- Menopause or other hormonal changes
- Medication effects or withdrawal
- Dehydration
- Low blood sugar
- Autonomic dysfunction
- Small-fiber neuropathy
- Anxiety or panic episodes
- Another infection or inflammatory illness
A symptom beginning during or after Lyme disease may be clinically important, but the timing alone does not prove that Lyme disease is the only explanation.
How Can Temperature Intolerance Be Evaluated?
Patients may find it helpful to record:
- The measured temperature during an episode
- Whether they feel hot, cold, chilled, flushed, or sweaty
- The environmental temperature
- The time and duration of the episode
- Possible triggers such as standing, exercise, meals, showers, or stress
- Associated heart-rate or blood-pressure changes
- Other symptoms occurring at the same time
Depending on the clinical presentation, a physician may consider:
- Complete blood count and metabolic testing
- Thyroid testing
- Evaluation for Babesia or another infection
- Orthostatic heart-rate and blood-pressure measurements
- Tilt-table or autonomic reflex testing
- Sweat-function testing
- Skin biopsy when small-fiber neuropathy is suspected
There is no single test that can determine whether temperature intolerance is caused by Lyme disease.
Why This Symptom Is Often Misunderstood
Heat and cold intolerance rarely appear on traditional Lyme disease symptom lists. Routine laboratory testing and thermometer readings may also be normal.
As a result, patients may be told that their symptoms are caused only by anxiety, stress, menopause, or deconditioning.
These conditions may contribute in some patients and should be evaluated. However, a normal thermometer reading does not exclude abnormal temperature sensation, sweating, skin circulation, or autonomic function.
When other causes have been considered, autonomic or small-fiber dysfunction may be a reasonable clinical consideration.
What Recovery May Look Like
Temperature sensitivity may improve as the underlying illness and autonomic stability improve, although recovery patterns vary.
Patients may notice:
- Fewer heat-related symptoms
- Less severe internal chills
- Fewer temperature swings
- More normal sweating
- Improved tolerance of showers and weather changes
Improvement is not always linear, and temporary worsening may occur during another illness, dehydration, extreme weather, or physiologic stress.
Frequently Asked Questions
Can Lyme disease make you feel feverish without a fever?
Some patients report feeling hot, chilled, flushed, or sweaty despite a normal measured temperature. These sensations may involve autonomic regulation or altered temperature perception, but they are not specific to Lyme disease.
Can Lyme disease cause heat intolerance?
Heat intolerance has been reported in patients with dysautonomia following Lyme disease. Heat may worsen dizziness, palpitations, fatigue, weakness, or brain fog in patients with autonomic or orthostatic intolerance.
Can Lyme disease cause cold intolerance?
Some patients report cold intolerance or internal chills despite a normal temperature. Thyroid disease, anemia, medication effects, circulatory problems, and other causes should also be evaluated.
Can you experience both heat and cold intolerance?
Yes. Some patients alternate between feeling overheated and chilled even though their measured temperature remains normal.
Does temperature intolerance mean Lyme disease is still active?
No. Temperature intolerance is nonspecific and cannot determine whether an active infection is present.
Can small-fiber neuropathy affect sweating?
Yes. Small autonomic fibers help control sweat glands and blood vessels near the skin. Abnormalities can produce excessive, reduced, or uneven sweating.
Are sweats more suggestive of Babesia?
Fever, chills, and sweats are recognized manifestations of babesiosis, but they cannot diagnose the infection. Clinical assessment and appropriate testing are required.
Clinical Perspective and Takeaway
Patients with Lyme disease may experience real heat or cold intolerance despite having a normal measured body temperature.
A normal thermometer reading does not evaluate temperature perception, sweat-gland function, skin circulation, or autonomic regulation.
Small-fiber or autonomic dysfunction is one possible explanation, but direct Lyme-specific research remains limited. Temperature intolerance does not prove ongoing infection or hypothalamic damage.
Evaluation should distinguish temperature intolerance from documented fever and consider Babesia, thyroid disease, anemia, medications, hormonal changes, autonomic dysfunction, and other medical causes.
Related Articles
- Autonomic Dysfunction in Lyme Disease
- POTS and Lyme Disease
- Night Sweats and Lyme Disease
- Fatigue in Lyme Disease
References
- Cheshire WP Jr. Thermoregulatory disorders and autonomic dysfunction. Auton Neurosci. 2016;196:82-92. doi:10.1016/j.autneu.2016.01.001.
- Adler BL, et al. Dysautonomia following Lyme disease: A key component of post-treatment Lyme disease syndrome? Front Neurol. 2024;15:1344862. doi:10.3389/fneur.2024.1344862.
- Novak P, Felsenstein D, Mao C, Octavien NR, Zubcevik N. Association of small fiber neuropathy and post treatment Lyme disease syndrome. PLoS One. 2019;14(2):e0212222. doi:10.1371/journal.pone.0212222.
- Bryarly M, Phillips LT, Fu Q, Vernino S, Levine BD. Postural orthostatic tachycardia syndrome: JACC focus seminar. J Am Coll Cardiol. 2019;73(10):1207-1228. doi:10.1016/j.jacc.2018.11.059.
- Centers for Disease Control and Prevention. Signs and symptoms of babesiosis.
This article is for informational purposes only and does not constitute medical advice. Patients should consult a qualified healthcare professional about diagnosis and 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
Oh, how I suffer with my body’s thermometer. My poor husband.
I have a question.
How am I able to sit in a far infra red sauna , at 67 degrees centigrade, for 30 minutes and then jump into a cold shower and feel great , and then experience extreme restlessness and irritability when the room temperature is 30 degrees centigrade??
Enjoy your articles.
Thank you for caring.
Margaret
The sensory system is so poorly understood
I used to always be cold. Then when I came down with Lyme Disease I could not tolerate the heat. I almost felt that I could never cool down and I would be in a panic. One day I was walking my dogs around my neighborhood in the winter. It was about 35 degrees and I was in a long sleeve T-shirt. My neighbor stopped me and asked, “Aren’t you cold?” I never thought about it. It felt like it was 65 degrees. I got to the point that I almost moved away from DC’s hot and humid summers because I felt so desperate. I have been in remission for many years now. I find that every summer that goes by, I am tolerating the heat more so and happy I never moved because I do love where I live.
So relieved to read that this is Lyme related. I’ve been miserable in my skin for years! Thank you for the information!
I was bit by a tick a year and 3 months ago. I received antibiotics and felt so sick! I’m experiencing very cold chills and assumed it was flu or my body fighting an infection. I am outside a lot and m finding I was either too hot or too cold. Just resting now. I hope it passes. Also, my heart hums when tested. I use to feel it vibrate at night so much it would wake me up. I thought it was anxiety or fast heart. I saw a heart specialist 4 years ago and he said I’m fine. I’ve never been given Lyme diagnosis just preventative measure. I’m having a lot of right knee problems and assumed it was from a fall. So many variables to think of.
I’ve had Lyme for about 10 years and in the past few years heat/cold intolerance has started to become a major symptom/problem. After about 4 hours in bed I get uncomfortably hot, especially my feet, and have to hang them out the cover. This combines with body itching, runny eyes, tinnitus and waking up.
I know if I just stick it out, after about 2 hours I will then get cold and have to pull on another cover. I then fall asleep again and when I finally get up I am really cold and have to do warm up exercises or I will just keep getting colder. Sometimes I struggle to decide if I’m hot or cold, it often comes with an overall sense of malaise.
autonomic issues typically involve Malaise
Oh yes for many years!
Heat g’ets My heart beating and the pulse get crazy (160). Dissyness. I Can cool My self Down with cold water on the hands or feet. I have to eat/drink also, it helps. W’et sooks or wrist bandage helps
Cold is worse. The body goes completely Down. It Can take 4 hours with Electric pillow/blankets to g’et warm again. The body Can be exhausted for days or weeks. I always have warm clothing in My car, and wool neck warmer, wool wrist warmer, cap, gloves, Scharf etc
Lyme disease can be overlooked as a cause.
I completely know about this issue. I also had a problem by body reacting to temperature . While suffering with lyme symtems I would be very cold in the summer at times even when outside temps were 80 and above , I would have get into a warm tub to warm up. In the winter I would be hot and have take heavy cloths off to cool down. Now after treatment including many supplements and almost four months of doxy twice a day I switched back to normal. I also did not sweat in the summer at all until after treatment. Even in a sauna for getting rid of toxins . Now ten years later I still react to temps as you describe I get very cold quickly under fifty degrees and above 65 I still get sick feeling and very unstable. I was luckl to find ND that understood lyme issues And knew what to do Most MD are useless when it comes to lyme
I’ve had Lyme disease for 20 yrs . they give me 12 hrs to live when I got it .. it’s been a horrible 20 years .. the heat now is making me so sick I feel like hell.. too bad the government made this shit with no cure .. they should have to compensate us all ..