A Case of Isolated Oral Secondary Syphilis

Key words: secondary syphilis, Treponema pallidum, aphthous ulcers, isolated oral lesions

A 40-year-old man presented to our hospital with a 7-week history of oral lesions with mild pain. He was initially diagnosed with aphthous ulcers by a dentist. Skin and genital lesions were absent, but he disclosed having unprotected intercourse with a female sex worker 5 months before presentation.

Physical examination revealed irregular, whitish ulcerations on the lower lip and tongue (Figure 1 and 2). Rapid plasma reagin [titer: 1:32] and Treponema pallidum hemagglutination were positive, and the HIV test result was negative. Based on a reasonable incubation period, clinical oral findings, and serological tests, a diagnosis of oral secondary syphilis was made. The oral lesions resolved within 1 week of treatment with amoxicillin.

Figure 1. An irregular, whitish, coalescing ulcer surrounded by an erythematous area on the lower labial mucosa.

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Figure 2. Multiple irregular whitish ulcers on the ventral surface of the tongue.

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Oral lesions of primary syphilis (so called oral chancres) are typically solitary, painless, indurated ulcers that heal spontaneously within 4-5 weeks ⁽¹⁾. In contrast, oral lesions of secondary syphilis are typically painful, multiple, and generally accompanied by cutaneous eruption ⁽¹⁾. Isolated oral lesions have been reported to occur in only 7% of patients with secondary syphilis ⁽²⁾, but the condition is potentially underestimated or misdiagnosed ⁽³⁾. Healthcare professionals should consider oral syphilis, including the secondary stage, in the differential diagnosis of isolated oral lesions. A key to early diagnosis and treatment is confirmation of sexual history and prompt syphilis serological testing.

Article Information

Conflicts of Interest

None

Author Contributions

Kiyozumi Suzuki: Writing-Original draft, Methodology

Akihiro Kanzawa: Methodology, Writing-review & editing

Hiromasa

Otsuka: Methodology, Writing-review & editing

Yuji Hirai: Methodology, Writing-review & editing

All authors critically reviewed the manuscript.

Approval by Institutional Review Board (IRB)

In this study, IRB approval was not required.

Informed Consent

Consent was obtained from the patient for the use of images for publication.

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