The Jarisch–Herxheimer Reaction After Antibiotic Treatment of Spirochetal Infections: A Review of Recent Cases and Our Understanding of Pathogenesis

Within 24 hours after antibiotic treatment of the spirochetal infections syphilis, Lyme disease, leptospirosis, and relapsing fever (RF), patients experience shaking chills, a rise in temperature, and intensification of skin rashes known as the Jarisch-Herxheimer reaction (JHR) with symptoms resolving a few hours later. Case reports indicate that the JHR can also include uterine contractions in pregnancy, worsening liver and renal function, acute respiratory distress syndrome, myocardial injury, hypotension, meningitis, alterations in consciousness, seizures, and strokes. Experimental evidence indicates it is caused by nonendotoxin pyrogen and spirochetal lipoproteins. Mediation of the JHR in RF by the pro-inflammatory cytokines tumor necrosis factor (TNF), interleukin (IL)-6, and IL-8 has been proposed, consistent with measurements in patients' blood and inhibition by anti-TNF antibodies. Accelerated phagocytosis of spirochetes by polymorphonuclear (PMN) leukocytes before rise in cytokines is responsible for removal of organisms from the blood, suggesting an early inflammatory signal from PMNs. Rarely fatal, except in neonates and in pregnancy for African women whose babies showed high perinatal mortality because of low birth weight, the JHR can be regarded as an adverse effect of antibiotics, necessary for achieving a cure of spirochetal infections.