Acute pustular eruption following a Jarisch-Herxheimer reaction in the treatment of syphilis

The Jarisch-Herxheimer reaction (JHR) is an acute febrile inflammatory reaction that sometimes follows the treatment of syphilis and other spirochete infections with antibiotics. Although first described over a century ago, relatively little is still known about this adverse event. It is thought that antimicrobial therapy renders the dividing spirochetes susceptible to phagocytosis, with consequent release of lipoproteins, cytokines, and immune complexes.1 Symptoms present within 2 hours of antimicrobial administration and include fever, chills, vasodilation with flushing, tachycardia, mild hypotension, and possible worsening of skin lesions.