What is latent syphilis (Sexually Transmitted Disease)?

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From the Guidelines

Latent syphilis is a stage of syphilis infection where the bacteria Treponema pallidum remains in the body without causing visible symptoms, and it is divided into early latent (acquired within the past year) and late latent (present for more than a year or of unknown duration) 1. This stage follows the primary and secondary stages and can last for years or even decades.

  • The diagnosis of latent syphilis is based on seroreactivity without other evidence of disease, and patients who have latent syphilis and who acquired syphilis within the preceding year are classified as having early latent syphilis 1.
  • Patients can be diagnosed as having early latent syphilis if, within the year preceding the evaluation, they had a) a documented seroconversion, b) unequivocal symptoms of primary or secondary syphilis, or c) a sex partner documented to have primary, secondary, or early latent syphilis 1.
  • The recommended treatment for early latent syphilis is a single intramuscular injection of benzathine penicillin G 2.4 million units, and for late latent syphilis, the treatment consists of three weekly doses of benzathine penicillin G 2.4 million units 2.
  • For penicillin-allergic patients, alternatives include doxycycline 100 mg orally twice daily for 14 days (early latent) or 28 days (late latent) 3.
  • Regular follow-up blood tests are essential to ensure the infection is properly treated, and although patients with latent syphilis are generally not contagious through sexual contact, the infection can still be transmitted from a pregnant woman to her fetus, potentially causing congenital syphilis 1.
  • If left untreated, about 30% of cases may progress to tertiary syphilis with serious complications affecting the heart, brain, and other organs.
  • All patients with latent syphilis should have careful examination of all accessible mucosal surfaces to evaluate for internal mucosal lesions, and all patients who have syphilis should be tested for HIV infection 1.

From the Research

Definition of Latent Syphilis

  • Latent syphilis is a stage of syphilis where all clinical manifestations subside, and infection is apparent only on serologic testing 4.
  • It is classified as early latent syphilis (less than 12 months) or late latent syphilis 5.

Characteristics of Latent Syphilis

  • In latent syphilis, the disease is not contagious, except in the early latent stage 5.
  • The diagnosis of latent syphilis involves serologic testing, as there are no visible symptoms 4.
  • Quantitative nontreponemal test titers should be obtained to monitor the disease, and these titers should decline fourfold within 12 to 24 months after treatment of latent syphilis 4.

Treatment of Latent Syphilis

  • The treatment of latent syphilis is based on penicillin or doxycycline in allergic patients 5.
  • A single dose of 2.4 million units of benzathine penicillin G is the recommended treatment for early latent syphilis 6.
  • Alternative regimens for nonpregnant patients with no evidence of central nervous system involvement include doxycycline, tetracycline, ceftriaxone, and azithromycin, although azithromycin resistance has been reported 6, 7.

Management of Latent Syphilis

  • Cerebrospinal fluid (CSF) examination should be performed in all persons with serologic evidence of syphilis infection and neurologic symptoms 6.
  • In those persons with early syphilis who do not achieve a ≥ 4-fold serologic decline in their rapid plasma reagin (RPR) titers 6-12 months after adequate therapy and those with late latent infection who do not achieve a similar decline within 12-24 months, CSF examination should be considered 6.
  • Follow-up is an essential part of management and should be particularly assiduous, for at least 24 months, in those co-infected with HIV 8.

References

Research

Diagnosis and management of syphilis.

American family physician, 2003

Research

Syphilis.

Enfermedades infecciosas y microbiologia clinica (English ed.), 2019

Research

Management of adult syphilis.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.