Jarisch-Herxheimer reaction

Introduction

A reaction following initiation of treatment for spirochetal infection (generally syphilis).

Etiology

• unknown
• induction of inflammatory mediators (i.e. tumor necrosis factor) by treponemal antigens

Epidemiology

• 50% of patients with primary syphilis
• 90% of patients with secondary syphilis
• 25% of patients with early latent syphilis
• particularly common in pregnant women

Pathology

• dying spirochetes release endotoxin

Clinical manifestations

• onset occurs within 2 hours of treatment
• fever
  • average increase of 1.5 C
  • fever peaks at 7 hours
  • defervescence in 12-24 hours
• chills
• myalgias
• headache
• tachycardia
• tachypnea
• neutrophilia (average WBC count of 12,500/mm3)
• vasodilation with mild hypotension
• erythema & edema of mucocutaneous lesions may increase with secondary syphilis
• resolution of symptoms within 48 hours

Management

• bedrest
• aspirin
• stop antibiotics until symptoms resolve
• patient education

More general terms

• inflammation

Additional terms

• spirochete infection