Jarisch-Herxheimer reaction /jä″ris herks″hīmər/ [Adolph Jarisch, Austrian dermatologist, 1850–1902; Karl Herxheimer, German dermatologist, 1861–1944] , a transient, short-term immunological reaction commonly seen after antibiotic treatment of early and later stages of syphilis and less often in other diseases, such as borreliosis, brucellosis, typhoid fever, and trichinosis. It is seen in 50% of patients with primary syphilis and 90% of those with secondary syphilis. Manifestations include fever, chills, headache, myalgias, and exacerbation of cutaneous lesions. The reaction has been attributed to liberation of endotoxin-like substances or antigens from the killed or dying microorganisms, but its exact pathogenesis is unclear.
