The characteristics of men who have sex with men presenting with oral syphilis: a systematic review

The aim of this systematic review was to highlight the demographic, behavioural, co-infection and clinical characteristics of MSM presenting with oral syphilis. Four bibliographic databases (MEDLINE via Ovid, Embase via Ovid, Cochrane CENTRAL, and CINAHL) was conducted in August 2025. Manuscripts describing MSM with oral syphilis were included in any language. Two reviewers independently screened full-texts for eligibility, and narratively synthesised data. Risk of bias was assessed using the Joanna-Briggs toolkit. The review was registered on PROSPERO (CRD420251106205). A total of 34 manuscripts were included in this review, which included 47 MSM with oral syphilis, and their median age was 29 years (IQR = 26–37). This review highlighted specific demographic (living with HIV), behavioural (oral sex, condomless anal sex, biting, multiple and non-regular sexual partners, recreational drug use/chemsex), co-infection (new HIV diagnosis, previous syphilis, concurrent sexually transmitted infections, other infections) characteristics of MSM with oral syphilis. The clinical features of oral syphilis included painful and painless; tonsillar, lip, tongue, buccal lesions; and with/without lymphadenopathy. Seventeen of the MSM in this review were unnecessarily investigated for a malignancy involving biopsy and histological examination. Oral syphilis has heterogenous clinical presentations, and these data serve as an important resource for future clinical guidelines, research and public health interventions.