Lyme disease (LD) is an infection transmitted to humans through the bite of an infected black-legged tick, caused by the bacterium Borrelia burgdorferi. This illness can affect multiple body systems if not treated early. Night sweats are a frequently reported symptom associated with an active Borrelia infection. These episodes of excessive sweating are a marker of the body’s systemic response to the invading bacteria.
The Mechanism Behind Lyme Disease-Related Sweating
Night sweats stem directly from the body’s immune reaction to the spirochete Borrelia burgdorferi. When the bacteria spread, they provoke a systemic inflammatory response involving the release of pro-inflammatory cytokines into the bloodstream. These cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), act as pyrogens (fever-inducing substances). Pyrogens influence the hypothalamus, the brain’s temperature-regulating center, resetting the body’s internal thermostat to a higher temperature. This reset results in a fever. When the fever breaks, the body initiates a rapid cooling mechanism to return to its normal set point, manifesting as intense, drenching perspiration. The Borrelia spirochete can also directly affect the autonomic nervous system, which controls involuntary functions like sweating, further disturbing temperature regulation.
Night Sweats in the Context of Lyme Disease Stages
Night sweats can appear in both the initial and later phases of a Borrelia infection. In the early, localized stage, occurring days to weeks after the tick bite, the sweats are often part of a flu-like syndrome, accompanying symptoms such as chills, headache, and muscle aches. Approximately 60% of adult patients with early Lyme disease report experiencing sweats and chills. As the infection progresses to the disseminated stage, the nature of the night sweats can change. They may become more pronounced, often described as drenching enough to soak clothing and bedding, and frequently occur regardless of the ambient room temperature. Symptoms in this later stage may follow a cyclical or relapsing pattern, waxing and waning over periods of weeks or months. This persistent presentation can distinguish the symptom from a simple acute illness.
Other Common Causes of Night Sweating
Night sweats are a non-specific symptom, meaning many other conditions can also cause them. It is important to consider alternative diagnoses before attributing the symptom solely to Lyme disease. Hormonal fluctuations are a common cause, particularly in women experiencing perimenopause or menopause, but men with low testosterone can also experience them. Certain medications are known to trigger nocturnal perspiration, including some antidepressants, aspirin, and pain relievers. Other infections, such as tuberculosis, mononucleosis, and Babesiosis (a common tick-borne co-infection), must also be considered. More serious, albeit less common, conditions like certain malignancies, particularly lymphomas, can present with persistent night sweats, underscoring the need for a thorough medical evaluation.
Resolution of Night Sweats Following Treatment
The resolution of night sweats is tied to the effectiveness of antibiotic treatment in clearing the underlying infection. Once medication begins to kill the Borrelia spirochetes, the inflammatory stimulus driving the fevers and subsequent sweats is removed. Patients should expect to see an improvement in this symptom as they progress through their prescribed regimen. A temporary worsening of night sweats can occur shortly after initiating therapy due to the Jarisch–Herxheimer reaction (JHR). This phenomenon is a short-lived inflammatory event caused by the massive die-off of the bacteria, which releases endotoxins and triggers a surge of inflammatory cytokines. JHR symptoms, including an exacerbation of sweats, fever, and chills, usually begin within 24 hours and resolve spontaneously within a day or two. If night sweats persist long after treatment has concluded, it may suggest a separate health issue or a co-infection that requires specific management.