Retrospective study of the clinical and epidemiological features of syphilis in patients with HIV infection in Saint Petersburg

Background. In the recent years, cases of syphilis and HIV infection have become more common in dermatovenerological practice due to increasing prevalence of HIV infection in the population.

Aim. Assessment of the clinical and epidemiological features of syphilis against HIV infection in modern settings.

Methods. A post-hoc analysis was conducted on the medical histories of 280 HIV-positive patients with syphilis who were under dispensary supervision at the St. Petersburg Center for AIDS and Infectious Diseases in 2018–2023.

Results. The group of patients with a combined syphilis and HIV infection was characterized by predominance of males (91.8%), young age (Q₂ = 34 years), stage 4 HIV infection (66.5%), promiscuous behavior (60.8%), and homosexual contacts (67.7%). The most common clinical form of syphilis was neurosyphilis (37.2% of cases), and 61.5 % of patients had asymptomatic meningitis. The differences in the clinical presentation of syphilis in HIV-infected patients compared to the “classical” presentation were due to both immunodeficiency and behavioral characteristics of the patients which explains common occurrence of extragenital (21.1%) and multiple (63.2%) chancres as well as high frequency of recurring infection (29.0%). In 54.6% of patients, syphilis occurred without skin or mucosal lesions, making diagnosis difficult.

Conclusion. Despite the steady improvement in our knowledge of syphilis and HIV, managing patients with a combination of these infections remains a challenging task for a venereologist. Common latent course of syphilis and high prevalence of recurring infections underline the importance of regular serological screening for syphilis in HIV-infected patients. High incidence of neurosyphilis in the study group combined with its asymptomatic course requires examination of cerebrospinal fluid in all patients with coinfection.