Can syphilis be transmitted through oral sex?

Transmission of Syphilis Through Oral Sex

Yes, syphilis can definitely be transmitted through oral sex. Oral sexual practices can lead to both symptomatic and asymptomatic syphilis infections in the oral cavity and pharynx 1.

Mechanism of Transmission

Syphilis is caused by the bacterium Treponema pallidum, which can be transmitted through:

• Direct contact with infectious lesions (chancres) during oral sex
• Contact with mucous membranes of an infected partner
• Exposure to secretions containing the spirochete

The primary and secondary stages of syphilis are the most infectious 2. During these stages, the bacteria can easily pass from lesions in the genital area to the oral cavity during oral sex, or from oral lesions to a partner's genitals.

Clinical Manifestations of Oral Syphilis

Syphilis in the oral cavity can present in various ways:

• Primary stage: A painless, solitary chancre (ulcer) may develop at the site of bacterial entry, commonly on the lips, tongue, or oral mucosa 3
• Secondary stage: Multiple lesions can appear, including:
  • Mucous patches on the oral mucosa
  • Condyloma latum (raised, flat-topped papules)
  • Lesions on the hard palate and labial commissure (less common, <5% of cases) 3
• Tertiary stage: Gummatous lesions may develop in the oral cavity

Risk Factors and Epidemiology

The practice of unprotected oral sex is a significant risk factor for syphilis transmission 3. With increasing oral sexual practices, primary chancres are more frequently observed in the oral cavity 4.

WHO estimates approximately 11 million new syphilis cases globally each year among adults aged 15-49 years 2. The incidence of syphilis has been increasing in several regions including North America, Western Europe, China, and Australia 2.

Diagnosis of Oral Syphilis

Diagnosis of oral syphilis involves:

1. Clinical examination of oral lesions
2. Serological testing:
   • Nontreponemal tests (RPR, VDRL)
   • Treponemal-specific tests for confirmation
3. In some cases, direct detection of T. pallidum from lesions using dark-field microscopy or PCR

Prevention and Management

To prevent syphilis transmission through oral sex:

• Use barrier methods (condoms, dental dams) during oral sex
• Regular screening for individuals with high-risk sexual behaviors
• Prompt treatment of infected individuals and their sexual partners

Treatment for syphilis acquired through oral sex is the same as for syphilis acquired through other routes:

• First-line treatment: Benzathine penicillin G administered intramuscularly 2, 5
• Alternative regimens for non-pregnant patients without neurosyphilis include doxycycline, tetracycline, ceftriaxone, and azithromycin 5

Important Considerations

• Asymptomatic oral infections can serve as an undetected reservoir for new infections 1
• Syphilis can be transmitted even when no visible lesions are present
• Oral lesions may be mistaken for other conditions, leading to delayed diagnosis
• All sexual partners should be notified, tested, and treated if necessary

Follow-up

After treatment, patients should have:

• Quantitative nontreponemal test titers that should decline fourfold within six months after treatment of primary or secondary syphilis 5
• Clinical evaluation to ensure resolution of symptoms
• Testing for other sexually transmitted infections, including HIV

Remember that syphilis can be effectively treated, especially in its early stages, but prevention through safer sexual practices remains the best approach to control this infection.