Group of at-home STD tests (including syphilis test) to help guide syphilis treatment

How is syphilis treated?

Written on March 19, 2023 by Gillian (Gigi) Singer, MPH, Sexuality Educator & Certified Sexologist. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

About syphilis

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum [1]. It can be transmitted through unprotected sexual contact or from a pregnant person to their infant. Syphilis can be a serious disease if left untreated, causing long-term health complications. However, it is easily treatable with antibiotics in the early stages.

Keep reading to learn how to recognize the symptoms of syphilis, when to seek medical attention, and the available treatment options for this condition. By understanding how to treat syphilis, you can take control of your health and prevent contracting and/or transmitting syphilis to others.

Stages of syphilis

Syphilis infections advance through a sequence of stages, each characterized by varying symptoms and severity. These stages may coincide, or the infection may become dormant and not display any symptoms at all.

Primary syphilis

Primary syphilis often appears as a single painless ulcer at the site of infection, but it “can also present with multiple, atypical, or painful lesions” [2].

Secondary syphilis

Secondary syphilis might appear as a rash on the skin, lesions like canker sores, and/or swollen lymph nodes [2].

Tertiary syphilis

Tertiary syphilis can cause problems with the heart, sores on the skin or organs, difficulty walking, and general cognitive and physical problems [2].

Latent syphilis infections

Latent infections occur when you have a disease/infection but don’t show any symptoms. To find out if you have a latent syphilis infection, you can get a blood test. If you got the infection within the last year, that's called early latent syphilis. If it's been longer than a year or it is unknown how long you've had it, it's called late latent syphilis or latent syphilis of unknown duration [2].

Neurosyphilis, ocular syphilis, and otosyphilis

When/if syphilis spreads to the brain, nervous system, eyes, or ears, the following symptoms may appear [3]:

  • Severe headache
  • Muscle weakness and/or trouble with muscle movements
  • Changes to your mental state (trouble focusing, confusion, personality change) and/or dementia (problems with memory, thinking, and/or decision-making)
  • Eye pain and/or redness
  • Changes in your vision or even blindness
  • Hearing loss
  • Ringing, buzzing, roaring, or hissing in the ears (“tinnitus”)
  • Dizziness or vertigo (feeling like you or your surroundings are moving or spinning)

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Diagnosing syphilis

In the absence of symptoms, a syphilis test can help determine if the infection is present.

Blood test

A nontreponemal test is a type of blood test used to check for syphilis. However, a positive result on this test doesn't always mean that a person has syphilis. Many other medical conditions and factors can also cause a positive test result—such as other infections, autoimmune diseases, vaccinations, drug use, pregnancy, and age.

To confirm a diagnosis of syphilis, a treponemal test is needed. Nontreponemal test results can also be used to monitor treatment response. The highest level of antibodies should be identified by diluting the serum and reporting the results in numbers.

Nontreponemal tests test for antibody levels, whereas treponemal tests test for the bacterium Treponema pallidum.

If nontreponemal test results don't match up with the symptoms of syphilis, healthcare providers might use other tests or prescribe presumptive treatment. For people with HIV, serologic tests are usually accurate for diagnosing syphilis and monitoring treatment response.

In severe cases of infection, cerebrospinal fluid can be tested, though “no single test can be used to diagnose neurosyphilis in all instances” [2].

Treating syphilis

So how is syphilis treated? Penicillin G is a medicine used to treat syphilis, a sexually transmitted infection. The effectiveness of penicillin for treating syphilis has been established through many years of clinical experience, even before randomized controlled trials became common.

The type of penicillin used, dosage, and how long it's taken are all dependent on the stage of the infection. The later in the infection that you begin treatment, the longer your treatment must be. It's important to choose the right type of penicillin because the bacteria can “hide” in certain parts of the body.

Combining different types of penicillin is not recommended for treating syphilis. There have been cases where healthcare providers accidentally prescribed the wrong combination of penicillin, so it's important to be aware of the different types and their names.

You may want to consider booking an appointment for Everlywell's online STD treatment option.

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  1. Syphilis. Mayo Clinic. URL. Accessed March 10, 2023.
  2. Syphilis - STI treatment guidelines. Centers for Disease Control and Prevention. URL. Published March 30, 2022. Accessed March 10, 2023.
  3. STD facts - Syphilis. Centers for Disease Control and Prevention. URL. Published February 10, 2022. Accessed March 10, 2023.
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