Description

• A chronic, systemic infectious disease caused by the spirochete Treponema pallidum
• Transmitted sexually by direct contact with an active lesion; also transmitted vertically (maternal–fetal) and via blood transfusions
• Untreated disease includes four overlapping stages.
  • Primary: single (usually) painless chancre at point of entry; appears in 10 to 90 days; chancre heals without treatment in 3 to 6 weeks.
  • Secondary: appears 2 to 8 weeks after primary chancre; nonpruritic rash on palms or soles of feet, mucous membrane lesions, headache, fever, lymphadenopathy, alopecia
  • Latent: seroreactive without evidence of disease
    • Early latent: acquired within the last year
    • Late latent: exposure >12 months prior to diagnosis
  • Tertiary (late): Serology may be negative (fluorescent treponemal antibody absorption [FTA-ABS] test typically positive).
    • Gumma, cardiovascular, and late neurosyphilis; may be fatal
  • Neurosyphilis: any type of CNS involvement; can occur at any stage
    • Psychosis, delirium, dementia
• Syphilis can affect nearly every organ/tissue.

Pediatric Considerations
In noncongenital cases, consider child abuse.

Pregnancy Considerations

• Screen all pregnant patients with venereal disease research laboratory (VDRL) test or rapid plasma reagin (RPR) test early in pregnancy, (i.e., first prenatal visit). If high risk, repeat at 28 weeks and at delivery (1),(2)[A].
• Use the same nontreponemal test for initial screening and for follow-up (1),(2)[A].

Epidemiology

Incidence

• Syphilis rate decreased through 2000 and have since increased (primarily in men who have sex with men [MSM]) (3).
  • All stages: 40 per 100,000
• Congenital: 49/100,000 live births (3)
• Primary and secondary syphilis statistics (3)
  • HIV coinfection
    • MSM: 44.2%
    • Men who have sex with women only (MSW): 7.6%
    • Women: 4.3%
  • Male (per 100,000 population)
    • Overall: 20.1 (highest for males ages 25 to 29 years)
    • Whites, non-Hispanic: 11.0; blacks, non-Hispanic: 53.5
    • Hispanics: 23.4; Asians: 8.9
    • American Indians/Alaska natives: 27.1
    • Native Hawaiians/Pacific Islanders: 35.9
    • Multirace: 18.1
  • Female (per 100,000 population)
    • Overall: 3.9 (highest for females ages 25 to 29 years)
    • Whites, non-Hispanic: 2.3; blacks, non-Hispanic: 10.2
    • Hispanics: 3.8; Asians: 0.6
    • American Indians/Alaska natives: 15.4
    • Native Hawaiians/Pacific Islanders: 9.6
    • Multirace: 3.3

Prevalence

• Predominant sex: male (83%) > female (17%) (3)
• Highest prevalence in MSM (3)

Etiology and Pathophysiology

T. pallidum enters through intact mucous membranes or breaks in skin. The organism quickly enters the lymphatics to cause systemic disease. Highly infectious; exposure to as few as 60 spirochetes is associated with ~50% chance of infection.

Risk Factors

MSM, multiple sexual partners, exposure to infected body fluids, injection drug use, transplacental transmission, adult inmates, high-risk sexual behavior, people living with HIV (PLWH)

General Prevention

Education regarding safe sex; condoms reduce but do not eliminate transmission (4)[A].

Commonly Associated Conditions

HIV infection, hepatitis B, other sexually transmitted infections (STIs)