Syphilitic chancre of the mouth

A 24-year-old man presented with a three-week history of a 1-cm painless, ulcerative lesion on his lower lip (Figure 1) and a three-day history of symmetrically distributed nonpruritic macules on his trunk (Figure 2) and limbs. He was HIV-negative and was otherwise healthy. He had performed unprotected orogenital sex with a female partner about three weeks before the onset of the ulcer. On examination, generalized nontender lymphadenopathy was noted along with the rash and chancre. A serologic test for syphilis showed a reactive rapid plasma reagin test result (titer 1:64) and a positive agglutination test result for Treponema pallidum. Syphilis was diagnosed, with findings consistent with both primary (oral chancre) and secondary (lymphadenopathy and macular rash) disease. He received treatment with intramuscular injection of penicillin G benzathine. The mucocutaneous lesions improved rapidly and resolved at the end of the treatment.

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Figure 1:

A 1-cm nontender, nonpurulent, oval ulcer with clean base and raised rolled border on the lip of a 24-year-old man.

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Figure 2:

Violaceous macules on the patient’s trunk.

Transmission of acquired syphilis occurs mostly through sexual intercourse.1^,2 Syphilitic chancre develops 3–90 days after exposure (mean 3 weeks),1^,2 with genitalia as the most common inoculation sites.2 Extragenital chancres occur in 12%–14% of patients with primary syphilis, the oral mucosa being the most frequent location as a consequence of orogenital contact.1^,3 Diagnosis of syphilitic chancre is based on the patient’s history of orogenital sexual contact, a reasonable incubation period, clinical features and results of serologic tests for syphilis. The differential diagnosis includes chancroid, herpes simplex, tuberculous chancre, deep mycoses, squamous cell carcinoma, traumatic ulcer, aphthous stomatitis and Behçet syndrome.3

Without treatment, syphilitic chancre spontaneously resolves in two to eight weeks. The secondary stage develops 2 to 12 weeks (mean 8 weeks) after inoculation.2 The secondary stage may overlap with the primary stage, as seen in our patient.