Oral Syphilis: The Great Imitator – A Case Series

Syphilis is a highly contagious disease caused by infection with the anaerobic filamentous spirochete, Treponema pallidum. It is transmitted horizontally by sexual contact and vertically in pregnancy. Often referred to as the ‘great imitator’, syphilis commonly mimics the clinical presentation of other conditions, making it vulnerable to misdiagnosis or delayed diagnosis. Oral manifestations of syphilitic infection can be seen in all stages (primary, secondary and tertiary) of the disease course.

Recent years have seen a significant increase in cases of syphilis infection, with 892 notifications in Ireland in 2022, a 13.9% increase from the previous year. In the UK in 2022, rates of new diagnoses were the highest since disease surveillance began in 1948. Alongside this increase in cases of infection, oral manifestations are also occurring at a high frequency.

Given that oral manifestations may be the initial presentation of the disease, oral medicine practitioners play an important role in the early diagnosis of infection, thus reducing the risk of the development of tertiary infection which involves neurological and cardiovascular systems, and which can be life-threatening. Furthermore early diagnosis also facilitates contact tracing and effective treatment, reducing disease transmission.

This case series presents six patients presenting to our unit with oral manifestations of syphilis infection. All cases occurred in men over the age of 50 years. The oral manifestations ranged from a single indurated oro-pharyngeal ulcer (chancre) closely mimicking a squamous cell carcinoma, to localised and widespread ‘snail track’ ulceration, mucous patches, and mucosal tagging. The investigation and management of these cases is presented.