The Jarisch-Herxheimer reaction

The Jarisch-Gerxheimer reaction (named after the Austrian and German dermatologists who described the phenomenon) is a transient systemic immune reaction of the body that develops in the first 24 hours after the initiation of specific antibiotic therapy for spirochete infections (syphilis, borreliosis, leptospirosis).

Etiology and pathophysiology

The pathogenesis of the reaction is not allergic (it is not anaphylaxis to penicillin). The condition is caused by rapid bacteriolysis (destruction) of spirochetes under the action of the antibiotic. The mass death of bacteria results in the simultaneous release of endotoxins, lipoproteins, and DNA fragments into the bloodstream. This provokes a systemic immune response – a “cytokine storm” with a sharp increase in the level of tumor necrosis factor (TNF-α), interleukins IL-6 and IL-8.

Clinical significance

The clinical picture develops 2-8 hours after the first injection and resembles a flu-like syndrome: sudden chills, rise in body temperature to 39-40°C, headache, myalgia, tachycardia and transient hypotension. Syphilis is characterized by temporary aggravation (brightness, swelling) of skin rashes and increased infiltration in the area of primary chancres or syphilitic vaginitis. The condition resolves on its own within a day and serves as an indirect confirmation of the effectiveness of therapy.