FUO and Syphilis
In summary, syphilis is an uncommon etiology for fever of unknown origin. Evidence-based clinical resources, including UpToDate and American Family Physician, do not thoroughly discuss syphilis in the differential diagnosis of FUO1,2,8. Extensive literature search reveals minimal and largely outdated case reports for this duo9,10. In such case reports, syphilis was similarly not discovered as the FUO etiology until multiple weeks of clinical workup.
Given this increasing incidence of syphilis, physicians need to remain vigilant. In addition, the stigma associated with this diagnosis may make patients reticent to provide relevant historical data. When considering the risk factors for syphilis, many patients belonging to these stigmatized populations are also medically underserved. Physicians bear the responsibility of investigating this diagnosis, while obtaining a history in a patient-sensitive manner. Treatment for this condition is simple and effective, whereas the sequelae of untreated syphilis may be catastrophic.