Discussion
Syphilis is a sexually transmitted infection caused by the spirochete Treponema pallidum. The condition is divided into primary, secondary and tertiary stages and can present with a variety of skin lesions and other clinical signs. Asymptomatic latent phases can occur at any time if left untreated. Early latent syphilis is defined as less than one year after infection, while late latent syphilis occurs more than one year after infection. Latent syphilis can only be detected by positive serology.
Primary syphilis is typically characterised by one or more painless ulcers, known as chancres. These appear at the site of inoculation 3–90 days after exposure and usually resolve spontaneously within 3–6 weeks. Regional lymphadenopathy can also occur. Secondary syphilis results from systemic spread of the spirochete and typically appears weeks to months after the primary stage. Typical findings include general symptoms, widespread lymphadenopathy and a characteristic diffuse maculopapular rash, mainly affecting the trunk and extremities, often with involvement of the palms and soles (2, 3).
The patient in this case report exhibited several of the findings described above. The presence of lymphadenopathy and general symptoms meant it was important to rule out lymphoma. The combination of benign-appearing lymph nodes on ultrasound, histological findings showing no malignancy, and a normal tonsil biopsy phenotype on flow cytometry ruled out this diagnosis. In addition, active syphilis requiring treatment was fully consistent with the clinical picture presented by the patient.
If left untreated, syphilis can progress to the tertiary stage, typically 10–12 years after primary infection. This may result in a wide range of symptomatic manifestations, which can involve the cardiovascular system or lead to granulomatous disease of the skin, subcutaneous tissue, bone or viscera (2). Infection of the cerebrospinal fluid can cause neurosyphilis, which can occur at any stage of syphilis and result in a range of hearing problems, visual disturbances or other acute neurological conditions. Patients with such symptoms should undergo lumbar puncture (4, 5). Untreated syphilis can cause significant suffering for the patient, as described in the Oslo study and the study conducted in Tuskegee, Alabama (6).
The incidence of syphilis has been gradually increasing both worldwide and in Norway since the mid-1990s. In 2023, a total of 208 new cases were reported in Norway, the majority of which were men who have sex with men. Infections are also rising among heterosexual men, with 30 reported cases, compared to 169 among men who have sex with men. The incidence among heterosexual women has remained stable over recent years.
According to the Norwegian Institute of Public Health's 2023 annual report, about half of those infected that year were diagnosed with either primary or secondary syphilis, while the remainder had early latent syphilis. Late latent syphilis is not reported to the Norwegian Surveillance System for Communicable Diseases (MSIS) as this stage is not considered infectious (7).
Syphilis can cause a wide range of symptoms affecting the skin and mucous membranes. This case report highlights the importance of considering syphilis as a key differential diagnosis in patients with unexplained throat pain accompanied by enlarged cervical lymph nodes.