Syphilis remains a public health concern globally, and in Brazil, the disease has been presenting a significant increase in incidence since 2010. This infection affects more than 10 million people worldwide per year1, with 60% or more incident cases occurring in men who have sex with men (MSM), mostly associated with human immunodeficiency virus (HIV) co-infection and high-risk sexual behavior2.
The disease presents in four distinct stages that are characterized by particular symptoms, clinical manifestations, and levels of infectivity: primary, secondary, tertiary, and latent syphilis3. The clinical differentiation between the oral lesions in primary and secondary syphilis is based on the presence of painful symptoms and the number of lesions4.
Oral chancres in primary syphilis are characterized as painless ulcers, measuring 1 to 2 centimeters, with a firm and rolled border5. They manifest as a single ulcer, usually on the lip or more rarely on the tongue3. Oral chancres are observed in approximately 4% to 12% of patients with primary syphilis, located where the bacteria penetrate the mucosa6.
Secondary syphilis presents multiple and generally symptomatic ulcerations4. Oral ulcers are observed in 30% of cases of secondary syphilis, usually associated with other clinical manifestations. In these cases, the lesions are maculopapular, affecting the hard palate and, sometimes, the soft palate3.
Gumma-associated bony destruction and a possible predisposition to oral squamous cell carcinoma are associated with tertiary syphilis. A gumma manifests initially as one or more painless swellings, especially on the hard palate7.
Previous studies demonstrated that patients with syphilis present a higher risk of being infected by other sexually transmitted diseases (STDs), especially HIV, since syphilitic lesions are vulnerable sites for virus penetration8.
The clinical diagnosis of syphilis is challenging for the dentist due to the variety of clinical characteristics of oral lesions, which may be similar to other ulcerative injuries6. The differential diagnosis of oral lesions of secondary syphilis includes erythematous lupus, multiform erythema, stomatitis, pemphigus, idiopathic leukoplakia, lichen planus, and candidiasis, among others9.
Laboratory diagnosis confirmation of syphilis is performed using serological tests. Nevertheless, the diagnosis also needs a high index of clinical suspicion during anamnesis4, since clinical and histological findings may be subtle and imprecise, especially considering other more common diagnoses10. Therefore, dentists should include questions on a patient’s recent sexual history in the anamnesis and be prepared to recognize and diagnose oral and systemic manifestations of STDs, especially syphilis3.
Dentists undergo academic training that makes their participation in multi-professional teams important for diagnosis and treatment of STDs11. Dental staff play a fundamental role in public health systems by guiding patients, performing accurate and early diagnosis, and referring patients to adequate treatment1,12. Since oral lesions are highly contagious, the reliability of correct diagnosis aids adequate management, reduces the infection chain, and reduces the risk of transmission to health professionals.