• Profile

Syphilis diagnosis and CDC treatment guidelines

M3 India Newsdesk Jan 18, 2019

The CDC (Centers for Disease Control and Prevention) guidelines for Syphilis provide quick recommendations for clinicians to diagnose and treat the disease. 

Syphilis, because of the variety of clinical presentations it shows can often look like other infections in the advanced stages. And though the disease has been fairly well controlled since the discovery of Penicillin, it hasn’t been eradicated completely.

The CDC guidelines stress that medical professionals should routinely test for syphilis in:

  • Pregnant women in the first visit, beginning of the third trimester, and delivery (if the individual is at risk)
  • Sexually active men who engage in sex with other men
  • Sexually active HIV positive individuals

Syphilis is a sexually transmitted disease in which an ulcerating chancre is seen, mainly on the genitals and which spreads through the lymphatic system to almost all tissues of the body and can result in serious clinical manifestations.

Three stages: Clinical manifestations & diagnosis

Currently, syphilis and herpes are regarded as the most common STIs even though viral STDs are rapidly increasing. Mixed infections with both occurring is also common. In clinics, patients usually present with the primary stage of the disease which is more alarming to them because of its site.

  1. Dermatologists should rule out the probability of syphilis in cases of secondary rashes in all symptomatic eruptions.
  2. A thorough physical examination and sexual history is needed in all patients who are at risk of syphilis.
  3. To diagnose early syphilis and congenital syphilis, darkfield examination and other tests such as PCR are done to detect T. pallidum bacteria directly from lesion exudates or tissues.
  4. Laboratory examination for syphilis is very important for make a diagnosis because syphilis has many varied clinical manifestations and may be hard to diagnose just clinically.

Primary stage

In this stage, a chancre is seen in the region of inoculation. Chancres can be atypical or present as subtle lesions which usually appear at the site of exposure within 10 to 90 days (average after 3 weeks) of infection. The time taken for a chancre to heal, even if untreated, ranges from a few days to weeks. In utero transmission is expected to occur in pregnant women since patients are highly infectious.

  1. Diagnosis is done either by direct examination, non-treponemal or treponemal tests.
  2. If Treponema pallidum is detected in the lesions, this confirms the diagnosis of syphilis. However, non-detection of Treponema pallidum does not rule out syphilis.
  3. PCR-based testing is highly reliable.
  4. In cases, where a genital ulcer is present and the non-treponemal test is positive, primary syphilis may not be indicated but serology can be repeated for a period of two to twelve weeks to attempt to diagnose syphilis.

Secondary stage 

In this stage, a polymorphic rash, lymphadenopathy and other systemic manifestations may be seen. Rashes are seen on the trunk and other areas of the body, but the palms of the hands and soles of the feet may be initially affected. Usually, it takes 2 to 6 weeks even without treatment for the symptoms to clear, but this can take up to 3 months also. In cases where there is contact with moist lesions, the patient is highly infectious.

  1. Diagnosis is done by direct examination, non-treponemal and treponemal tests.
  2. Detection of T. pallidum can be done from the skin and mucosal lesions.
  3. In cases of atypical lesions, a PCR-based test may be useful.

Latent stage

In the early latent stages, no symptoms are seen in the patients, but within one year of infection onset, patients will test positive for non-treponemal and treponemal tests. Signs of primary and secondary syphilis may reappear and may not be noticed, but the patients are potentially infectious.

Manifestations of cardiovascular and neurologic sequelae are seen in the tertiary stages, and gumma formation may also be present in any of the organ systems. This tertiary stage is the most destructive stage of syphilis.

  1. Diagnosis is done by non-treponemal and treponemal tests.
  2. The sensitivity of non-treponemal tests decreases as the disease progresses but in early latent syphilis, they are reactive.
  3. Confirmation is needed when a reactive treponemal test presents with a reactive non-treponemal test.

Congenital syphilis

As per guidelines, at the time of their first prenatal visit, all pregnant women should be tested for syphilis. Testing for syphilis should also be done at the time of delivery in all women who deliver a stillbirth after 20 weeks.

Penicillin treatment should be started instantly without a delay as soon as a pregnant woman is diagnosed with syphilis. The chances of preventing the majority of congenital syphilis cases are enhanced when penicillin treatment is given 30 days before delivery.

  1. Diagnosis is done by direct examination and non-treponemal test.
  2. Mother and child should both be tested using their venous blood.
  3. Direct examination of different specimens from the neonates can detect T. pallidum.
  4. High reliability is seen with the PCR-based test.


Neurosyphilis can occur at any stage of syphilis and involve the nervous system, however, it may take weeks or years before noticing the symptoms, even though the nervous system is infected within hours after infection. Early neurosyphilis occurs in the primary and secondary stages of syphilis but it is frequently seen after a few weeks to a few years of infection onset.

After 10-30 years of infection onset, late neurosyphilis is normally seen in the late latent stage. HIV test should be mandatory for all the patients diagnosed with neurosyphyllis.

  1. Diagnosis is done by non-treponemal and treponemal tests.
  2. A combination of tests are required for diagnosis.
  3. The standard serological test for syphilis, VDRL-CSF is highly specific but it is not sensitive.
  4. High reliability is seen with PCR-based tests.

Ocular syphilis

Any of the stages of syphilis can present as ocular syphilis. Ocular symptoms such as eye pain, blurry vision, eye redness, and vision loss may occur. A vigilant neurological exam, an ophthalmologic evaluation, and CSF testing via lumbar puncture should be done in patients with syphilis and ocular symptoms.

Since severe outcomes such as permanent blindness may occur, treatment of ocular syphilis should not be delayed even if waiting for investigation results. Treatment for ocular syphilis is similar to that of neurosyphilis.

Tertiary syphilis

  1. Diagnosis is done by non-treponemal and trponemal tests.
  2. Most often always, the treponemal test is reactive for which they should always be considered for making the diagnosis.
  3. Direct microscopy of the lesions is unsuitable.

Treatment guideline

Treatment as per CDC (Centers for Disease Control and Prevention) are as follows:

  1. Primary and secondary syphilis: Benzathine penicillin G is given in a single dosage of 2.4 units IM (intramuscularly)
  2. Latent syphilis: In cases of late latent of more than one year, and late latent syphilis of unknown duration, a total of 7.2 million units of Benzathine penicillin G is given in a dose of 2.4 million unit IM at intervals of 1 week.
  3. Neurosyphilis: Treatment is achieved with aqueous crystalline penicillin G 18 to 24 million units per day, given for 10-14 days as 3 to 4 units IV every 4 hours or continuously.
  4. Ocular syphilis: 18 to 24 million units of aqueous crystalline penicillin G per day is given as 3 to 4 million units IV at intervals of 4 hours, or by continuous infusion for 10 to 14 days. In patients with HIV infection, extra doses of benzathine penicillin are not recommended.

Patient counselling

The nature of the disease, transmission, treatment, follow up and risk reduction should be included in patient counselling and education. The treating physician should:

  • Assess the capability of the patient for changing his/her behavior
  • Preventing strategies such as self-restraint, using condoms, limiting sex partners and being mutually monogamous with 1 uninfected partner should be discussed with the patients
  • Clinicians should discuss the correct and consistent use of latex condoms with the patients as they can lower the chances of transmission by making a barrier between the infected area or the area where there is chance of exposure
Only Doctors with an M3 India account can read this article. Sign up for free or login with your existing account.
4 reasons why Doctors love M3 India
  • Exclusive Write-ups & Webinars by KOLs

  • Nonloggedininfinity icon
    Daily Quiz by specialty
  • Nonloggedinlock icon
    Paid Market Research Surveys
  • Case discussions, News & Journals' summaries
Sign-up / Log In
M3 app logo
Choose easy access to M3 India from your mobile!

M3 instruc arrow
Add M3 India to your Home screen
Tap  Chrome menu  and select "Add to Home screen" to pin the M3 India App to your Home screen