Syphilis is a bacterial sexually transmitted infection that can have long-term health consequences if left untreated. Understanding syphilis symptoms, diagnosis, and treatment options is key to preventing complications. Syphilis and its impact on mental health become particularly significant in advanced stages, affecting cognitive function and emotional well-being. Understanding how to prevent and treat syphilis transmission is important for protecting both physical and mental health.
Understanding Syphilis
Syphilis is caused by the bacterium Treponema pallidum, which spreads primarily through direct contact with infected sores during sexual activity [1]. This sexually transmitted infection (STI) affects millions of people worldwide. According to the CDC, in 2023, over 209,000 cases of syphilis were reported in the United States, representing the highest number of cases since the 1950s [2].
The bacteria spread through body fluids, most commonly during unprotected sexual contact. Syphilis also shares transmission patterns with some sexually transmitted diseases. However, unlike some STIs, such as the herpes virus or the most common STI, chlamydia, syphilis can also be transmitted when infected sores come into contact with open cuts or scrapes on the skin.
Syphilis transmission can occur even when symptoms are not visible, making it particularly dangerous for unsuspecting partners. Pregnant women can also transmit syphilis to their unborn children, potentially causing serious birth defects or stillbirth [1].
The infection progresses through distinct stages, each with its own symptoms and varying levels of contagiousness. Therefore, understanding these stages is essential for recognizing syphilis symptoms and seeking appropriate medical care. Without proper treatment, syphilis in its later stages can cause irreversible damage to a person’s vital organs, including the brain and heart. Fortunately, syphilis responds well to antibiotic treatment when caught early, making awareness and testing vital for preventing long-term complications and reducing transmission.
Syphilis Stages and Symptoms
Syphilis progresses through three distinct stages, each presenting different symptoms [3].
Primary Stage
The first stage occurs 10 days to 3 months after initial infection [3]. The hallmark symptom is the appearance of painless ulcers called “chancres” around the specific area that’s infected. These distinctive sores are typically round and firm, causing no pain or discomfort to the infected person. Usually, only one chancre appears, though multiple sores can sometimes occur depending on the exposure.
Chancres can appear on the genitals, mouth, or anywhere the bacteria enter the body during sexual contact. The sores heal on their own within three to six weeks, even without any treatment [3]. Since chancres are painless and heal independently, many people don’t realize they have syphilis during this stage, making early detection challenging.
Secondary Stage
Within several weeks to months after chancres heal, about 25% of infected people develop secondary stage symptoms, while 75% experience a silent but continuing infection [3]. Signs of the secondary stage of syphilis include:
- Rash: A distinctive rash often appears on the palms of hands and soles of feet.
- Systemic symptoms: Fever, headache, swollen lymph nodes, loss of appetite, and extreme tiredness affect the entire body.
These secondary stage symptoms may come and go over several months or years.
Late-Stage Syphilis
Without treatment, syphilis progresses to the dangerous final stage, sometimes called “late syphilis.” This stage can develop anywhere from one to thirty years after initial infection and causes severe damage to a person’s vital organs [3].
The Mental Health Impact of Syphilis
Syphilis and its impact on mental health become most pronounced during the final or “late” stage, which is when the bacteria have a neurological impact [3]. This impact is known as neurosyphilis. It can occur at any stage, but it most commonly develops in late-stage infections.
Specifically, neurosyphilis occurs when syphilis bacteria invade the brain and nervous system, causing serious neurological and psychiatric complications. They include [4]:
- Memory impairment: Memory loss affects both recent and long-term recall, making it difficult to perform daily tasks or maintain employment. This memory deterioration often resembles dementia symptoms. It’s also progressive, which means it gets worse over time if left untreated.
- Mood disorders: Significant mood changes include depression, anxiety, irritability, and emotional instability. These changes can strain relationships and affect quality of life.
- Cognitive decline: Problems with thinking, reasoning, and decision-making abilities develop gradually. Concentration difficulties and confusion make it challenging to complete complex tasks.
- Personality changes: Dramatic shifts in personality and behavior can occur, including increased aggression, poor judgment, and inappropriate social behavior.
The diversity of symptoms can make neurosyphilis particularly challenging to diagnose. As noted by syphilis researcher Dr. Edward Hook III, “Neurosyphilis remains one of the great masqueraders in medicine, capable of causing virtually any neurologic or psychiatric syndrome” [5].
Early treatment can help prevent these devastating mental health complications, making syphilis diagnosis and prompt treatment important for protecting both physical and psychological well-being.
Diagnosis and Testing for Syphilis
Syphilis diagnosis requires specific blood tests performed by healthcare providers, as symptoms alone cannot definitively confirm infection [6]. Multiple testing methods help ensure accurate diagnosis.
Initial Blood Tests
Healthcare providers use two main types of blood tests for syphilis detection. Screening tests are the initial detection method and can identify antibodies that the body produces in response to syphilis infection. Common screening tests include the rapid plasma reagin (RPR) and venereal disease research laboratory (VDRL) tests. When screening tests show positive results, healthcare providers perform more specific tests to verify the diagnosis [6].
The Testing Process
During the comprehensive syphilis diagnosis process, healthcare professionals may [6]:
- Ask about symptoms, sexual history, and potential exposure to infection
- Physically examine for visible sores, rashes, or other signs of infection
- Draw a blood sample for laboratory testing
- Explain test results and recommend appropriate next steps
Who Should Get Tested
Regular syphilis and STI testing becomes important for people who:
- Have multiple sexual partners or engage in unprotected sex
- Have been diagnosed with other sexually transmitted infections (STIs)
- Are pregnant or planning a pregnancy
- Have a partner with syphilis
- Notice unusual sores, rashes, or other concerning symptoms
Syphilis diagnosis also may require repeat testing, as it can take several weeks after infection for antibodies to become detectable in blood tests. Early and accurate diagnosis enables prompt treatment, preventing progression to advanced stages and reducing transmission risk to sexual partners.
Treatment Options for Syphilis
Treating syphilis effectively requires antibiotic therapy prescribed and monitored by healthcare professionals [7]. The specific treatment approach depends on the stage of infection and individual patient factors.
Antibiotic Treatment
Penicillin is the most effective antibiotic for treating syphilis at all stages. Early-stage infections require a single injection, while advanced infections need three weekly injections to ensure complete bacterial elimination. When the brain and nervous system are affected, treatment usually involves receiving penicillin through an IV in a hospital for 10 to 14 days. This allows the antibiotic to reach the right levels in the body to be effective [7].
Treatment Monitoring
Successful treatment requires comprehensive follow-up care. Healthcare professionals repeat blood tests at 3, 6, and 12 months after treatment to make sure the infection has been cleared. Recent sexual partners must also be tested and treated (even without showing symptoms).
Patients should avoid sexual contact until treatment is complete and blood tests confirm it has been cleared from the body. Most people experience a complete cure with appropriate treatment. However, if the infection caused neurological damage before treatment was started, the damage may be permanent [7].
Syphilis Prevention Strategies
Preventing syphilis transmission requires a comprehensive approach combining safe sexual practices, regular testing, and clear partner communication [8]. Multiple prevention strategies can significantly reduce infection risk.
Primary Prevention Methods
The most effective prevention strategies include safe sexual practices:
- Abstinence: Complete avoidance of sexual contact eliminates syphilis transmission risk.
- Monogamy: Having sex with one uninfected, committed partner dramatically reduces risk.
- Barrier methods: Consistent and correct condom use during all sexual activities provides significant protection.
However, condoms don’t provide complete protection since syphilis chancres can appear on areas not covered by condoms, such as the pubic region, thighs, or testicles. Skin-to-skin contact with infected areas can transmit the bacteria even with condom use, though female condoms may provide broader protection than male condoms [8].
Communication and Testing
Effective prevention also requires open discussions about sexual health, testing history, and STI status to help partners make informed decisions about protection methods. Routine STI screening for sexually active people, especially those with multiple partners, supports early detection and treatment. When syphilis is diagnosed, notifying recent sexual partners allows them to test and seek treatment, breaking the chain of transmission.
Living with Awareness
Syphilis represents a serious but completely treatable sexually transmitted infection (STI) that requires prompt attention to prevent serious long-term consequences. Recognizing syphilis symptoms across all stages enables early detection, while understanding the progression from painless chancres to potentially life-threatening complications proves the importance of seeking medical care.
Syphilis and its impact on mental health become particularly severe in untreated cases, yet fortunately, syphilis diagnosis and appropriate treatment can lead to a full recovery. Preventing syphilis transmission through safe sexual practices, regular testing, and partner communication protects both people and communities from this preventable infection.
- Centers for Disease Control and Prevention. (2022). Syphilis – CDC detailed fact sheet. https://www.cdc.gov/syphilis/about/index.html. Accessed May 25 2025.
- Centers for Disease Control and Prevention. (2024). National Overview of STIs in 2023. https://www.cdc.gov/sti-statistics/annual/summary.html. Accessed May 25 2025.
- Peeling, R. W., Mabey, D., Kamb, M. L., Chen, X. S., Radolf, J. D., & Benzaken, A. S. (2017). Syphilis. Nature Reviews Disease Primers, 3, 17073. https://doi.org/10.1038/nrdp.2017.73. Accessed May 25 2025.
- Ghanem, K. G. (2010). Neurosyphilis: A historical perspective and review. CNS Neuroscience & Therapeutics, 16(5), e157-e168. https://doi.org/10.1111/j.1755-5949.2010.00183.x. Accessed May 25 2025.
- Hook, E. W. III. (2017). Syphilis. The Lancet, 389(10078), 1550-1557. https://doi.org/10.1016/S0140-6736(16)32411-4. Accessed May 25 2025.
- World Health Organization. (2016). Guidelines for the treatment of Treponema pallidum (syphilis). https://www.who.int/publications/i/item/9789241549714. Accessed May 25 2025.
- Workowski, K. A., & Bolan, G. A. (2015). Sexually transmitted diseases treatment guidelines, 2015. MMWR Recommendations and Reports, 64(RR-03), 1-137. https://pubmed.ncbi.nlm.nih.gov/26042815/. Accessed May 25 2025.
- National Institute of Allergy and Infectious Diseases. (2021). Syphilis. https://www.niaid.nih.gov/diseases-conditions/syphilis. Accessed May 25 2025.
The Clinical Affairs Team at MentalHealth.com is a dedicated group of medical professionals with diverse and extensive clinical experience. They actively contribute to the development of content, products, and services, and meticulously review all medical material before publication to ensure accuracy and alignment with current research and conversations in mental health. For more information, please visit the Editorial Policy.
MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.
Briana Casali is an experienced editor and professional writer with a background in academic editing and journalism for high-growth organizations.
Dr. Holly Schiff, PsyD, is a licensed clinical psychologist specializing in the treatment of children, young adults, and their families.
Medical Reviewer:
The Clinical Affairs Team at MentalHealth.com is a dedicated group of medical professionals with diverse and extensive clinical experience. They actively contribute to the development of content, products, and services, and meticulously review all medical material before publication to ensure accuracy and alignment with current research and conversations in mental health. For more information, please visit the Editorial Policy.
MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.