Syphilis -the \"great simulator\" for classical venereologists-is re-emerging in Western countries despite adequate treatment; several contributing factors have been identified, including changes in sexual behaviour, which won\'t be the topic of this article though. In 2021, a total of 6613 new cases of syphilis were reported in Spain, representing an incidence of 13.9×100 000 inhabitants (90.5%, men). Rates have increased progressively since 2000. The clinical presentation of syphilis is heterogeneous. Although chancroid, syphilitic roseola and syphilitic nails are typical lesions, other forms of the disease can be present such as non-ulcerative primary lesions like Follmann balanitis, chancres in the oral cavity, patchy secondary lingual lesions, or enanthema on the palate and uvula, among many others. Regarding diagnosis, molecular assays such as PCR have been replacing dark-field microscopy in ulcerative lesions while automated treponemal tests (EIA, CLIA) are being used in serological tests, along with classical tests (such as RPR and HAART) for confirmation and follow-up purposes. The interpretation of these tests should be assessed in the epidemiological and clinical context of the patient. HIV serology and STI screening should be requested for anyone with syphilis. Follow-up of patients under treatment is important to ensure healing and detect reinfection. Serological response to treatment should be assessed with the same non-treponemal test (RPR/VDRL); 3-, 6-, 12-, and 24-month follow-up is a common practice in people living with HIV (PLHIV). Sexual contacts should be assessed and treated as appropriate. Screening is advised for pregnant women within the first trimester of pregnancy. Pregnant women with an abortion after week 20 should all be tested for syphilis. The treatment of choice for all forms of syphilis, including pregnant women and PLHIV, is penicillin. Macrolides are ill-advised because of potential resistance.

BACKGROUND: Since 2000, substantial increases in syphilis have been reported in metropolitan areas of Western countries, with increases noted among men who have sex with men (MSM). Clinical manifestations of syphilis might be influenced by concomitant VIH infection and previous episodes of syphilis. The objectives of this study were to describe the epidemiological and clinical characteristics of the cases of syphilis diagnosed in Barcelona.
METHODS: Retrospective study of cases with early syphilis diagnosed in the referral STI Unit of Barcelona from January 2003 to December 2013. Revision of medical records with structured collection of epidemiological and clinical data. Univariate and multivariate statistical analyses comparing the characteristics of MSM cases with and without VIH infection and with and without previous syphilis.
RESULTS: A total of 1702 cases of syphilis (37% primary, 48% secondary and 14% early latent) were diagnosed, 93% of them in MSM. Among MSM 40% were coinfected with VIH, VIH-positive cases were associated with a previous syphilis (aOR, 5.2 [95% CI, 3.32-8.24]) and with unprotected anal intercourse (aOR, 1.75 [95%CI, 1.17-2.63]). Cases with a history of syphilis presented less often with primary syphilis compared to those without it (27.5% vs. 40%) (aOR, 0.58 [95% CI, 0.44-0.77]). One year after treatment, the clinical and serological evolution were similar between VIH-positive and VIH-negative cases.
CONCLUSIONS: The epidemic of syphilis in Barcelona disproportionately affects MSM and is closelly linked to VIH infection. The presentation of syphilis is influenced by VIH infection and by previous history of syphilis, without significant differences in their evolution after one year of treatment.

The evolution of syphilis after treatment could be affected by different factors, for example HIV. In consequence, HIV positive patients are sometimes treated with more doses of penicillin (PBG). The aim of the study is to describe and compare the serological evolution by different factors in patients with early syphilis in Barcelona.
The serological control was made over the following year. A time analysis was performed through the study of Kaplan- Meier curves.
The serological control was made in 208 patients, 42.5% of whom were HIV-positive. In a Kaplan-Meier curve the median of days needed to observe the cure was 99 [97-105] without differences depending on HIV, previous syphilis, stage or RPR titters. A better evolution was observed in patients treated with doxycycline P=.02.
The serological evolution is similar in HIV-negative and HIV-positive patients treated according to current recommendations, observing the cure at 3 month after treatment.