Syphilis guide: Risk factors and clinical manifestations

On this page

• Risk Factors
• Transmission
• Clinical Manifestations
  • Primary syphilis
  • Secondary syphilis
  • Latent syphilis
  • Congenital syphilis
  • Neurosyphilis
  • Tertiary syphilis
• References

Risk factors

STBBI screening is often based on individual risk factors for the person seeking care. It is recommended that health care practitioners discuss these factors with the person seeking care to determine their sexual health history and identify appropriate screening approaches.

Risk factors associated with syphilis include^{Footnote 1Footnote 2Footnote 3Footnote 4}:

Behavioural risk factors	Epidemiological risk factors
Barrierless sexual activity involving contact with oral, genital, or anal mucosa Having multiple sexual partners Sexual contact with a known case of syphilis or other STBBI Substance use, including chemsex	Previous syphilis infection or other STBBI HIV infection Population groups and/or communities experiencing high prevalence of syphilis (and other STBBI) Having experienced homelessness and/or street involvement

Transmission

Syphilis is transmitted by direct contact with an infectious lesion or through vertical transmission during pregnancy. Primary, secondary and early latent stages are considered infectious, with an estimated risk of transmission per partner of 51% to 64%^{Footnote 3}. Early latent syphilis is considered infectious because of the 25% chance of relapse to the secondary stage^{Footnote 4}.

The primary mode of syphilis transmission is by vaginal, anal and oral sexual contact^{Footnote 2}. Other routes of transmission (e.g. kissing and needle-sharing) are rare^{Footnote 5}.

Transplacental transmission can occur as early as nine (9) weeks gestation^{Footnote 6} and throughout pregnancy. Most infants with congenital syphilis are infected in utero, but they can also be infected by contact with an active genital lesion at the time of delivery. The risk of transmission is related to both stage of syphilis as well as gestational age at time of diagnosis and treatment, with the greatest risk of transmission in pregnant people acquiring syphilis near term^{Footnote 7}. The risk of transmission to the fetus is 70% to 100% in untreated pregnant people with primary or secondary syphilis and 40% with early latent syphilis^{Footnote 8,Footnote 9}.

In a recent systematic review, adverse pregnancy outcomes occurred in 76.8% of untreated pregnancies compared to 13.7% of uninfected pregnancies^{Footnote 10}. Even after treatment, there remains a significantly higher risk of adverse pregnancy outcomes compared to uninfected pregnancies^{Footnote 11}.

Clinical manifestations

The clinical manifestations of syphilis are usually described according to stage of disease: primary, secondary, latent, congenital, neurosyphilis and tertiary syphilis.

Note: Neurosyphilis may occur at any stage.

Health care practitioners should consider syphilis in people presenting with rashes or genital ulcerative disease and/or proctitis.

Primary syphilis

Usually occurs three (3) weeks after infection but can range from three (3) to 90 days. The primary manifestation is a painless lesion (chancre). In persons practicing receptive sex, the lesion(s) may be intra-anal, oral or on the internal genital tract and may go unnoticed. Regional lymphadenopathy may occur.

Secondary syphilis

This stage typically starts with the development of a rash. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots on the palms of the hands and the bottoms of the feet. Rashes with a different appearance may occur on other parts of the body and may be so faint that they are not noticed.

Signs and symptoms usually occur between two (2) to 12 weeks, but can occur up to six (6) months after infection and may include:

• Rash
• Fever
• Malaise
• Headaches
• Mucosal lesions
• Condylomata lata
• Lymphadenopathy
• Patchy or diffuse alopecia

Secondary syphilis can also manifest with signs and symptoms of meningitis (e.g. headaches), uveitis/retinitis (e.g. blurred vision, eye redness, flashes or floaters) or otic symptoms (e.g. hearing loss, tinnitus).

Latent syphilis

Early latent syphilis

Asymptomatic infection of less than one (1) year duration.

Late latent syphilis

Asymptomatic infection of more than one (1) year duration.

Congenital syphilis

Early congenital syphilis

If present, symptoms typically occur before the second year of life. Two-thirds of infections may be asymptomatic. Clinical manifestations may include:

• Anemia
• Neurosyphilis
• Rhinitis (sniffles)
• Osteochondritis
• Hepatosplenomegaly
• Mucocutaneous lesions
• Fulminant disseminated infection

Late congenital syphilis

Clinical manifestations are usually identified two (2) years after birth and can include:

• Anemia
• Neurosyphilis
• Bone involvement
• Interstitial keratitis
• Lymphadenopathy
• Hepatosplenomegaly
• Dental abnormalities (e.g. Hutchinson's teeth)

Neurosyphilis

Treponema pallidum can infect the central nervous system and cause neurosyphilis during any stage of syphilis. It can occur in cases of untreated primary infection, up to 20 years or more after infection.

Neurosyphilis may be asymptomatic or present with:

• Ataxia
• Vertigo
• Dementia
• Headaches
• Personality changes
• Argyll Robertson pupil
• Otic symptoms (e.g. tinnitus, hearing loss)
• Ocular symptoms (e.g. blurred vision, flashing lights, floaters)

HIV alters the natural course of syphilis and sometimes results in a more rapid progression to neurosyphilis and more aggressive and atypical signs of infection^{Footnote 12,Footnote 13}.

Early neurosyphilis

Early neurosyphilis occurs within the first year of infection. Approximately 5% of those affected will experience manifestations such as meningitis, cranial neuritis, ocular involvement and meningovascular disease^{Footnote 14}.

Late neurosyphilis

Late neurosyphilis occurs more than one (1) year after infection with 2% to 5% experiencing general paresis and 2% to 9% experiencing tabes dorsalis^{Footnote 14}.

Tertiary syphilis

Untreated primary infection may progress to neurosyphilis, cardiovascular syphilis or gumma.

Cardiovascular syphilis

Occurs from 10 to 20 years after exposure and may present with:

• Aortic aneurysm
• Aortic regurgitation
• Coronary artery ostial stenosis

Syphilitic gumma

Occurs from one (1) to 46 years after exposure but most cases will develop within 15 years.

Gummatous lesions cause tissue destruction and can occur on any organ. Clinical manifestation will depend on the site involved.

References