Primary syphilitic lesions in the oral cavity may inflict buccal and gingival mucosa, lips or perioral skin. They emerge in affected individuals after oral sex. The rates of other routes for disease transmission (via personal things such as toothbrushes, or by direct contact, or after medical manipulations) are negligibly low.

After sexual intercourse, the causative agent of syphilis T. pallidum invades the skin or mucosal through their minimal lesions. The infectious dose for it is extremely low: as little as 1-5 microbial cells can trigger the illness.

The incubation period depends on the inoculated dose. A large inoculum, e.g., about 107 bacterial cells, results in disease appearance in 5-7 days.

After approximately 1 month of incubation a hard chancre, essential tissue lesion of primary syphilis, appears. It is followed by regional lymphadenopathy.

Chancre evolves at the primary site of microbial entry. Its orofacial localization often occurs on lip vermilions and oral mucosa. Hard chancre is a painless ulcer about 0.5-3 cm with sharp margins, clean base, induration, and sometimes with purulent discharge.


In most cases chancre heals spontaneously within about 6 weeks. Nevertheless, in several weeks the disease comes into stage of secondary syphilis, which results from lymphogenous and hematogenous microbial dissemination.

Secondary syphilis is the systemic inflammatory process characterized by skin rash, headaches, fever, malaise, lymphadenopathy, mucosal lesions, and CNS disorders. It lasts from 2-3 months to more than 1 year. Cutaneous or mucosal syphilitic eruptions or syphilides harbor great amount of spirochetes, being highly infectious.

In oral cavity secondary mucosal lesions appear as the erythematous and maculo-papular syphilides. They render oval-shaped grayish-white elements on mucosal surface followed by periostitis.

If not treated, after latent period of various length (about 1 year or even more) the disease progresses into tertiary syphilis.

Tertiary syphilis affects various body’s organs and tissues, especially cardiovascular system and CNS. Specific slow-growing indurative injuries (or gummas) emerge in tissues and parenchimatous organs resulting in necrosis with subsequent connective tissue proliferation.

These lesions rarely appear in mouth. If arisen, they form growing nodules (tubercular syphilides) and gummas. When progressed, the lesions undergo deep necrosis with degradation of underlying soft tissues and bones, for instance, resulting in perforation of the soft palate.

Congenital syphilis in infants issues from vertical disease transmission in untreated women with a rate of 70 to 100% for primary syphilis.

The infected infants may be asymptomatic or show the numerous manifestations of early and late congenital disorder with multiple dental abnormalities. Herein they render screwdriver-shaped incisors with notched incisal edges (Hutchinson’s incisors). Mulberry deformation of molars is observed.

Overall, Hutchinson’s triad of abnormalities in congenital syphilis comprises lymphadenopathy and hepatomegaly accompanied with skeleton and teeth lesions.

▶Laboratory diagnosis of syphilis rests on a microscopical examination of specimens taken from primary or secondary syphilitic lesions and/or serological tests for specific antibodies.

▶Serological testing is the mainstay of laboratory diagnosis for latent, secondary, and tertiary syphilis. It confirms the presence of anti-treponemal antibodies in patient sera by means of highly specific serological reactions, e.g., T. pallidum immobilization test and ELISA test.

▶The treatment of the disease is based on the high sensitivity of T. pallidum to beta-lactam antibiotics. Penicillin G and its derivatives remain to be the drugs of choice for syphilis treatment.