JAMA Netw Open

Jarisch-Herxheimer reaction common after penicillin treatment for early syphilis

February 19, 2025

Study details: This secondary analysis of a multisite, randomized clinical trial involved 249 adults (median age, 32 years; 97.2% male; 61.4% living with HIV) with early syphilis treated with benzathine penicillin G. The study aimed to determine the incidence and characteristics of Jarisch-Herxheimer reaction (JHR) following treatment.

Results: JHR symptoms were observed in 59 participants (23.7%), with 86.0% experiencing onset within 12 hours of treatment. The most common symptoms included myalgias (50.8%), chills (45.8%), weakness (39.0%), and feverishness (35.6%). The reaction was associated with successful treatment response, secondary syphilis, and absence of HIV.

Clinical impact: Clinicians should counsel patients with early syphilis about the potential for JHR symptoms within 24 hours of benzathine penicillin G treatment. Awareness of this reaction can help manage patient expectations and improve adherence to treatment.

Source:

Dionne JA, et al. (2025, February 13). JAMA Netw Open. Jarisch-Herxheimer Reaction After Benzathine Penicillin G Treatment in Adults With Early Syphilis: Secondary Analysis of a Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/39946129/