What is the recommended testing and treatment for a patient concerned about potential exposure to syphilis?

Testing and Treatment for Syphilis After Potential Exposure

For patients concerned about potential exposure to syphilis, the recommended approach is serological testing with both nontreponemal (VDRL, RPR) and treponemal (FTA-ABS, TP-PA) tests, followed by appropriate treatment based on disease stage if positive. 1

Diagnostic Testing

Initial Testing

• Serological testing is the cornerstone of syphilis diagnosis:
  • Nontreponemal tests: RPR or VDRL (should be reported quantitatively)
  • Treponemal tests: FTA-ABS or TP-PA (for confirmation)

Testing Algorithm

1. Traditional approach (recommended by CDC):

   • Initial screening with nontreponemal test (RPR or VDRL)
   • If positive, confirm with treponemal test (FTA-ABS or TP-PA) 1, 2

2. Reverse sequence screening (alternative approach):

   • Initial screening with treponemal test (EIA/CIA)
   • If positive, follow with nontreponemal test
   • If discordant results (treponemal positive, nontreponemal negative), perform a second treponemal test 2

Additional Testing

• Direct detection methods for visible lesions:
  • Darkfield microscopy or direct fluorescent antibody tests of lesion exudate 1
• CSF examination is indicated for:
  • Patients with neurological symptoms
  • Evidence of active tertiary syphilis
  • HIV co-infection with late latent syphilis 1

Treatment Recommendations

Primary, Secondary, and Early Latent Syphilis (< 1 year duration)

• First-line treatment: Benzathine penicillin G 2.4 million units IM in a single dose 1
• For penicillin-allergic non-pregnant patients:
  • Doxycycline 100 mg orally twice daily for 14 days 1, 3
  • Tetracycline 500 mg orally four times daily for 14 days 1

Late Latent Syphilis or Latent Syphilis of Unknown Duration (> 1 year)

• First-line treatment: Benzathine penicillin G 7.2 million units total, administered as 3 doses of 2.4 million units IM at 1-week intervals 1
• For penicillin-allergic non-pregnant patients:
  • Doxycycline 100 mg orally twice daily for 28 days 1, 3

Neurosyphilis

• First-line treatment: Penicillin G aqueous 18-24 million units IV daily, administered as 3-4 million units every 4 hours for 10-14 days 1
• For penicillin-allergic patients: Desensitization followed by penicillin treatment (no effective alternatives) 1

Management of Sexual Partners

• Sexual partners exposed within 90 days of diagnosis of primary, secondary, or early latent syphilis should be treated presumptively, even if seronegative 4, 1
• Sexual partners exposed >90 days before diagnosis should be treated presumptively if serologic test results are not immediately available and follow-up is uncertain 4
• For partners of patients with latent syphilis of unknown duration with high nontreponemal titers (≥1:32), treat as early syphilis 4
• Long-term partners of patients with late latent syphilis should be evaluated clinically and serologically and treated based on findings 4, 1

Follow-up and Monitoring

• Quantitative nontreponemal tests should be performed at:
  • 6,12, and 24 months after treatment 1
• Criteria for treatment success:
  • Four-fold decline in nontreponemal titers within 6-12 months for primary/secondary syphilis
  • Four-fold decline within 12-24 months for latent/late syphilis 1, 5
• Retreatment considerations:
  • Four-fold increase in titer
  • Failure of initially high titer (≥1:32) to decrease four-fold within appropriate timeframe
  • Persistence or recurrence of symptoms 1

Special Considerations

• All patients with syphilis should be tested for HIV due to high co-infection rates 4, 1
• Pregnant patients with penicillin allergy should undergo desensitization followed by penicillin treatment 1
• HIV-infected patients may require more careful follow-up due to potentially higher rates of neurological complications and treatment failure 1

Common Pitfalls to Avoid

1. Relying solely on one type of serologic test - Both nontreponemal and treponemal tests are needed for accurate diagnosis
2. Missing neurosyphilis - Consider CSF examination in patients with neurological symptoms
3. Inadequate follow-up - Ensure proper serological monitoring after treatment
4. Failure to test and treat partners - Critical for preventing reinfection and further transmission
5. Not testing for HIV - Syphilis and HIV co-infection is common

Remember that early detection and appropriate treatment are essential for preventing progression to later stages of disease and reducing transmission to others.