A Jarisch-Herxheimer reaction is a reaction to endotoxin-like products released by the death of harmful bacteria during antibiotic treatment. The release of these bacterial toxins results in a systemic inflammatory response. A Jarisch Herxheimer reaction is usually not life-threatening.
A Jarisch-Herxheimer reaction usually starts between 24-72 hours after the start of antibiotic therapy of Lyme disease and can cause fever, chills, stiffness/rigor, muscle pain, hypotension, headache, heart palpitations, hyperventilation and anxiety. The intensity of the reaction indicates the severity of the inflammation.
A Jarisch-Herxheimer reaction is associated with the treatment of syphilis, leptospirosis, Lyme disease and relapsing fever. There have been reports of a Jarisch-Herxheimer reaction accompanying treatment of infections such as Q-fever, bartonellosis and brucellosis.
Ibuprofen, aspirin or acetaminophen can be taken to minimize the reaction. Drinking enough fluids and taking rest are also recommended.