Syphilis is a sexually transmitted infection (STI) that can lead to serious health issues if left untreated. While often associated with genital infections, it can also manifest in the mouth as primary oral syphilis. Its symptoms can be subtle and easily overlooked.
What is Primary Oral Syphilis?
Syphilis is caused by the bacterium Treponema pallidum. This bacterium enters the body through minor cuts or scrapes in the skin or moist mucous membranes, such as those in the mouth or genitals. Once inside, Treponema pallidum spreads throughout the body via the blood and lymphatic systems.
Primary oral syphilis occurs when the bacterium is transmitted through direct contact with an infectious sore, known as a chancre, during oral sexual activity. This primary stage involves the formation of a single chancre at the point of bacterial entry, which is highly contagious.
Identifying Oral Syphilis Symptoms
The characteristic lesion of primary oral syphilis is a chancre, which usually appears at the site where the bacteria entered the body. These chancres are typically firm, round, and often painless, which can lead to them going unnoticed. The lesion may resemble a pimple and often has a clean base with a raised, indurated border.
Common locations for oral chancres include the lips, tongue, tonsils, and throat. While usually solitary, some individuals may develop multiple lesions. The painless nature of the chancre means many patients are not diagnosed during this primary stage, even though it is highly infectious. Oral chancres can also mimic other oral conditions, making identification challenging without medical evaluation.
Medical Diagnosis and Treatment
Diagnosing primary oral syphilis involves a combination of methods. Direct microscopic examination of fluid from the sore, known as dark-field microscopy, can identify the Treponema pallidum bacteria due to their distinctive wavy structure and motility. This method is highly specific for primary syphilis.
Blood tests are also commonly used for diagnosis, including non-treponemal tests like the Rapid Plasma Reagin (RPR) and Venereal Disease Research Laboratory (VDRL) tests, which measure antibodies not specific to Treponema pallidum. If these screening tests are positive, treponemal tests such as the Fluorescent Treponemal Antibody Absorption (FTA-ABS) test or Treponema pallidum particle agglutination (TP-PA) test confirm the presence of specific antibodies to the syphilis bacterium. While serologic tests have high sensitivity in later stages, their sensitivity for detecting primary syphilis can be lower in the very early stages.
The standard treatment for primary syphilis is penicillin, which is highly effective. For early syphilis, a single intramuscular dose of benzathine penicillin G is typically administered. Penicillin is the only recommended therapy for syphilis during pregnancy, and pregnant individuals with a penicillin allergy may undergo desensitization to allow for penicillin treatment.
For non-pregnant individuals with a penicillin allergy, alternative treatments are available. Doxycycline is the preferred option, usually given orally twice daily for 14 days. Tetracycline is another alternative, though doxycycline is often favored due to better patient compliance. Azithromycin and ceftriaxone have also been used, but azithromycin’s use is cautioned due to rising resistance.
Preventing Oral Syphilis and Why Early Action Matters
Preventing oral syphilis involves adopting safer sexual practices. Consistent use of barrier methods like condoms during vaginal, anal, and oral sex reduces the risk of transmission. Dental dams, thin latex squares, can also be used during oral sex to create a barrier against infection. Open communication with sexual partners about their sexual history and STI status is also a preventative measure.
Early diagnosis and prompt treatment are important to prevent the progression of syphilis to more severe stages. Untreated syphilis can advance to secondary, latent, and tertiary stages, potentially causing widespread damage to various organ systems, including the brain, heart, and nerves. Early treatment with antibiotics like penicillin can cure the infection and prevent long-term health complications. Timely treatment of infected individuals also helps prevent further transmission within the community.