How to Know If You Have Oral Syphilis

Syphilis is a common sexually transmitted infection (STI) that is characterized by painless sores. It is typically contracted through genital, anal, or oral sexual activity. It is known to be a highly contagious bacterial infection.

This article discusses the symptoms, diagnosis, and treatment for oral syphilis.

Healthcare provider examining a person's throat

Martin Barraud / Getty Images

Syphilis Symptoms 

Oral syphilis occurs when someone contracts the infection orally. When this happens, the initial symptom is one or multiple sores, known as chancres. As the disease progresses, it can go through other stages, including secondary, latency, and tertiary.

During secondary oral syphilis, lesions that appear as white patches can develop on the inner lips and tongue. These white patches could also develop into sores or ulcers within the mouth.

The latency stage of syphilis presents with no symptoms at all, but if it progresses to the tertiary stage, lesions of dead skin cells can present on the roof of the mouth. While the bumps that develop in genital syphilis are typically painless, in more than 91% of oral cases, pain is present.  

Secondary Syphilis Symptoms

Other symptoms that can arise in a person with oral syphilis during the second stage include:

  • Fever
  • Fatigue
  • Weight loss
  • Hair loss
  • Swollen lymph nodes
  • Muscles aches and pains


The main cause of oral syphilis is oral sexual activity with a person that has an active syphilis infection.

The syphilis bacteria, known as Treponema pallidum, enters the body through open cuts or sores, and when it does, it causes infection. If that bacteria enters through a cut within the mouth, oral syphilis will develop.

How Else Is Oral Syphilis Transmitted?

While it is uncommon, oral syphilis can also develop in infants fed pre-chewed food from their loved ones with an active infection. Non-sexual and sexual biting has also been shown to cause syphilis transmission in some rare cases. Kissing when a person has an active infection or sore can also spread oral syphilis.


The diagnostic process for oral syphilis is similar to that of other types of syphilis infection. However, dentists are usually the first to notice or examine the lesions.

In some cases, a dentist will perform a biopsy to determine if an infection is present, but other tests and a health history collection will be needed.

If syphilis is suspected after examination, a blood test known as a rapid plasma regain (RPR) will be performed to check for syphilis-specific antibodies, which are specialized proteins designed to help fight off syphilis infections.

If the test comes back positive, treatment may begin, or more tests may be ordered to help confirm the diagnosis. Other tests include blood tests that look for specific signs of the infection within the blood or a specialized lab test that looks for the syphilis bacteria.


Syphilis is curable with the use of antibiotics. The length of time a person has had the infection and the stage of disease will play a role in how long their treatment will last:

  • Under two years/primary and secondary stages: Oral antibiotics may be taken for 10 to 14 days, or one single injection of penicillin may be administered.
  • Over two years/latency and tertiary stages: Oral antibiotics will be taken for 28 days, or three injections will be given once a week for three weeks.

Can Syphilis Come Back After Treatment?

While the initial syphilis infection can be cured after treatment, a person is not protected from getting it a second time if they engage in sexual activity with someone who has an active infection.

Possible Side Effects 

Oral syphilis can lead to some of the same side effects as other types of syphilis if it is left untreated. During the later stages, especially the tertiary stage, untreated oral syphilis can affect the health of the brain, heart, and other organ systems. The side effects can include:

  • Neurological decline, including dementia, mental changes, and issues with cognition
  • Issues with the heart's functionality that compromise proper blood flow
  • Hearing loss
  • Blindness
  • Lesions that develop in various areas of the body, such as the skin, bones, and organs
  • Death

How to Prevent Syphilis in the Mouth

The best way to prevent oral syphilis is to avoid sexual contact with a person who has an active infection. Using protection while participating in oral sexual activities can also help prevent contracting a bacterial infection from another person.

If you are sexually active and have multiple partners, practicing safe sex and participating in regular screenings can avoid any long-term complications that may arise if you do contract oral syphilis.

Risk Factors of Oral Syphilis

If you participate in oral sexual activity, you are at risk of contracting oral syphilis. However, some people may be more at risk than others, including:

  • People who are HIV positive
  • People who engage in oral sexual activity with partners that have syphilis or who engage in condomless oral sexual activity
  • Men who have condomless oral sex with other men


Oral syphilis is a type of syphilis that occurs within the mouth. When the bacterial infection is contracted in the mouth, the first sign of infection is typically one or more sores on the inside of the mouth. Secondary oral syphilis presents with worsened mouth lesions that can appear as white patches, sores, and ulcers. Other symptoms of syphilis can also be present, such as fever, headache, muscle aches and pains, and hair and weight loss.

Oral syphilis may originally be noticed by a dentist examining the mouth. Otherwise, diagnosing and treating oral syphilis is essentially the same as other types of syphilis and involves the use of a physical examination and blood tests. The only treatment is antibiotics.

While some people are at an increased risk of contracting oral syphilis, anyone that engages in condomless oral sex with a person who has an active infection can contract the infection. The best way to protect yourself against oral syphilis is to engage in safer-sex practices and get regular screenings.

A Word From Verywell 

Oral syphilis can be challenging to diagnose, so be sure to visit your healthcare provider if you develop any mouth sore. Treatment is available for oral syphilis; the faster you get treatment, the better it will be for your overall health.

Frequently Asked Questions

  • How common is oral syphilis?

    Syphilis is a common sexually transmitted infection. That said, oral syphilis is not as common. According to research, oral syphilis accounts for only 4%-12% of all syphilis cases.

  • How fast can you diagnose syphilis in the mouth?

    The speed at which oral syphilis can be diagnosed depends on several factors. The first is the incubation period, which is the time it takes for symptoms to appear. Since this number can range dramatically, it can be challenging to determine an actual timeline. Other factors include how quickly a person sees their healthcare provider for their symptoms and what tests are used. If testing is used first to rule out other conditions, the diagnosis will take longer.

  • Can you spread syphilis through kissing?

    While it is rare, kissing someone who has an active oral syphilis infection can spread it. This typically only occurs if the infected person has sores in their mouth during the kiss and the other person has open cuts or areas of entry within their mouth for the bacteria to get in.

  • Does oral syphilis go away on its own?

    While oral syphilis follows the same stage pattern as other types of syphilis and can go through a period of symptom-free latency, it does not resolve on its own. Therefore, all cases of syphilis, oral or otherwise, require treatment so that the infection does not progress to other areas of the body, compromising your overall health. 

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.