If you are undergoing treatment for chronic Lyme disease, your physician may have warned you about the possibility of a Herxheimer reaction. Also known as a “Herx” or Jarisch-Herxheimer reaction, this temporary symptom flare is one of the most common — and most misunderstood — events that occurs during effective antimicrobial treatment.
What Is a Herxheimer Reaction?
A Herxheimer reaction occurs when large numbers of bacteria are killed rapidly by antimicrobial treatment. As the bacteria die, they release endotoxins and cellular debris into the bloodstream faster than the body can clear them. This sudden increase in circulating toxins triggers a temporary inflammatory response that can intensify existing symptoms or produce new ones.
The reaction was first described in the late 19th century by dermatologists Adolf Jarisch and Karl Herxheimer, who observed it during the treatment of syphilis with mercury. It has since been documented across many spirochetal infections, including Lyme disease caused by Borrelia burgdorferi.
Why Does It Happen During Lyme Treatment?
Chronic Lyme disease involves persistent Borrelia organisms that have established themselves in multiple tissue compartments. When an effective treatment — particularly whole-body hyperthermia combined with IV antibiotics — reaches these organisms, the resulting die-off can be substantial. The body’s detoxification systems (liver, kidneys, lymphatic system) must process this sudden burden of bacterial fragments, lipoproteins, and inflammatory mediators.
At St. George Hospital, we consider a Herxheimer reaction during treatment to be a clinical indicator that therapy is reaching the infection. Patients who experience a moderate Herxheimer reaction after hyperthermia sessions are demonstrating that the combined thermal and antimicrobial assault is effectively targeting Borrelia organisms.
Common Symptoms
Herxheimer reactions vary from patient to patient, but commonly include:
- Increased fatigue and malaise
- Muscle and joint pain intensification
- Headache and cognitive fog
- Low-grade fever and chills
- Sweating, particularly night sweats
- Gastrointestinal discomfort
- Skin flushing or rashes
- Temporary mood changes or anxiety
These symptoms typically begin within hours of an effective treatment session and can last from a few hours to several days, depending on the bacterial burden and the patient’s detoxification capacity.
How We Manage Herxheimer Reactions
At St. George Hospital, we do not leave patients to simply endure a Herxheimer reaction. Our treatment protocols include specific measures designed to minimize the intensity and duration of these episodes:
- Detoxification infusions — Glutathione, alpha-lipoic acid, and other detoxification agents administered before and after hyperthermia sessions to support hepatic and renal clearance of toxins
- H.E.L.P. apheresis — Blood filtration that physically removes circulating inflammatory mediators, immune complexes, and bacterial debris from the bloodstream, providing rapid symptom relief
- IV hydration and electrolyte support — Maintaining adequate hydration and mineral balance to support kidney function during the detoxification process
- Physical therapy and lymphatic drainage — Manual lymphatic drainage and gentle movement therapy to support the lymphatic system’s clearance capacity
- Continuous monitoring — Vital signs, inflammatory markers, and symptom severity are tracked throughout your stay, allowing the medical team to adjust the protocol in real time
When to Be Concerned
Most Herxheimer reactions are self-limiting and resolve within 48 to 72 hours. However, as an inpatient at St. George Hospital, you are under continuous medical supervision. Our physicians and nursing team are trained to distinguish between a typical Herxheimer reaction and symptoms that may require additional intervention.
If symptoms become severe — high fever above 39 °C, significant blood pressure changes, severe neurological symptoms, or signs of an allergic reaction — the medical team can intervene immediately. This is one of the reasons why we deliver intensive Lyme treatment as an inpatient program rather than on an outpatient basis.
A Sign That Treatment Is Working
While a Herxheimer reaction is uncomfortable, it is important to understand what it represents: your treatment is reaching the infection and killing bacteria. Patients who experience a moderate Herxheimer reaction after their first hyperthermia session typically report significant improvement in their baseline symptoms in the days and weeks that follow.
Dr. Julian Douwes, Chief Medical Officer, notes: “We prepare every patient for the possibility of a Herxheimer reaction and explain exactly what it means. When patients understand the mechanism, they are far better equipped to work through it. And our detoxification protocols are specifically designed to minimize its intensity and duration.”