Proposed mechanisms and preventative options of Jarisch-Herxheimer reactions

Objective: To review the aetiologies and preventative methods associated with Jarisch-Herxheimer reactions (JHR). Data sources: Ovid Medline((R)) (1966-June Week 1 2004) was utilized to assess biomedical literature; a review of the bibliographies of articles was also performed. Data synthesis: JHR often occurs with the treatment of spirochete infections. However, the mechanism by which the reaction takes place is not clearly defined. Conclusion: Studies suggest with conflicting evidence that the JHR is caused by release of endotoxin-like material from the spirochete as well as cytokine elevation in the body. It appears the type of drug and the rate of spirochete clearance from the body have little effect on the incidence of the reaction. Many pretreatment options have been explored with limited efficacy with the exception of anti-tumour necrosis factor antibodies.