Syphilis - Symptoms, Causes & Treatment
By ScanSkinAI Editorial Team✓ Reviewed for medical safetyLast updated June 2026
A sexually transmitted bacterial infection that progresses through stages, with various skin manifestations including painless sores and widespread rash.
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Quick Answer
Syphilis is a highly contagious, sexually transmitted bacterial infection that develops in stages. It typically begins with a single, painless sore at the spot where the bacteria entered the body. If left untreated, it can spread to cause a widespread skin rash, frequently appearing on the palms and soles, accompanied by flu-like symptoms. While syphilis can cause severe long-term organ damage if ignored, it is highly treatable. A doctor can easily cure the infection with prescribed antibiotics, usually a shot of penicillin, preventing further health complications.
Clinical Context
Syphilis is caused by the spirochete bacterium Treponema pallidum. Rates have surged in recent years, with over 200,000 US cases in 2022. The disease progresses through defined stages if untreated: primary (chancre), secondary (rash and systemic symptoms), latent (asymptomatic), and tertiary (organ damage). The rash of secondary syphilis classically involves palms and soles - a key diagnostic clue. Syphilis is called 'the great imitator' because its varied presentations can mimic many conditions. Congenital syphilis (mother-to-infant) is increasing and is entirely preventable with prenatal screening and treatment.
Symptoms
- Primary: painless sore (chancre)
- Secondary: widespread rash including palms and soles
- Mucous patches
- Hair loss
- Latent: no symptoms
- Tertiary: serious complications
Severity & Progression
Causes & Risk Factors
- Treponema pallidum bacteria
- Sexual contact
- Mother-to-child transmission
Treatment & Management
Penicillin G is the treatment of choice for all stages and the only proven treatment for pregnant women and neurosyphilis. Primary, secondary, and early latent syphilis are treated with a single intramuscular injection of benzathine penicillin G 2.4 million units. Late latent syphilis requires three weekly injections. Neurosyphilis requires IV penicillin for 10-14 days. For penicillin-allergic patients, doxycycline is an alternative (except in pregnancy). Partners within relevant time windows should be tested and treated. Follow-up serology confirms cure.
- Penicillin (treatment of choice)
- Alternative antibiotics if allergic
- Partner notification and treatment
- Regular testing for at-risk individuals
Red Flags & Complications
Seek medical attention if you experience any of the following:
- Neurosyphilis (can occur at any stage)
- Cardiovascular syphilis (aortitis, aneurysm)
- Gummas (destructive granulomatous lesions)
- Congenital syphilis (deafness, bone deformities, death)
- Increased HIV transmission risk
- Organ damage in tertiary stage
Self-Care Tips
- Get tested regularly if sexually active with multiple partners
- Use condoms consistently (reduces but doesn't eliminate risk)
- Notify partners if diagnosed
- Complete all prescribed treatment
- Abstain from sexual activity until treatment is complete
- Get tested for other STIs including HIV
- Attend all follow-up appointments for repeat testing
When to See a Doctor
If you develop a painless sore on genitals or a widespread rash
Frequently Asked Questions
What does the first sign of syphilis look like?
The earliest sign, known as a chancre, is usually a single, firm, round, and painless sore. It appears at the exact site where the bacteria entered your body, such as the genitals, rectum, or mouth. Because it does not hurt and may be hidden inside the body, it is easily missed. The sore will heal on its own in three to six weeks, but the infection remains active.
My palms and soles have a rash, could that be syphilis?
Yes, a rash on the palms of the hands and soles of the feet is a classic sign of secondary syphilis. This rash is usually rough, red, or reddish-brown, and importantly, it typically does not itch. It may appear as the initial sore is healing or several weeks later. Syphilis is sometimes called 'the great imitator' because its rash can easily look like other skin conditions.
How exactly do you catch syphilis?
Syphilis is caused by the Treponema pallidum bacterium. You catch it through direct sexual contact with an active syphilis sore during vaginal, anal, or oral sex. It can also be passed from a pregnant mother to her unborn child, known as congenital syphilis, which can be devastating but is entirely preventable with routine prenatal care. It is not spread through toilet seats, swimming pools, or sharing utensils.
Can syphilis be cured completely?
Yes, syphilis is completely curable with the right antibiotics, most commonly an injection of penicillin. A single shot often cures early-stage infections, while later stages may require more doses or intravenous treatment. However, treatment will not undo any permanent organ damage that has already occurred. Your sexual partners must also be tested and treated so you do not continually pass the infection back and forth.
What happens if I just ignore it?
If ignored, syphilis progresses through stages and can hide asymptomatically in your body for years. Unchecked, it eventually moves into the tertiary stage, which is very dangerous. It can cause severe, life-threatening damage to your internal organs, including the heart, brain, nerves, and blood vessels. Complications like neurosyphilis can happen at any stage, causing blindness, stroke, or severe cognitive decline.
When should I see a doctor about possible syphilis?
You should see a healthcare provider immediately if you notice any unusual painless sores, unexplained rashes—especially on your hands or feet—or if a sexual partner informs you they have tested positive for syphilis. Because symptoms can disappear on their own even while the disease remains active and dangerous, any sexually active person with new symptoms or multiple partners should request routine screening.
Does wearing a condom fully protect me from getting it?
Using condoms correctly and consistently significantly reduces your risk of catching syphilis. However, condoms only protect the area they cover. Since syphilis sores can develop on the scrotum, vulva, anus, or mouth, transmission is still possible if the sore is located outside of the skin covered by a condom. Regular testing is the best way to stay safe if you have multiple sexual partners.
How can ScanSkinAI help me check for a syphilis rash?
ScanSkinAI can analyze photos of your skin symptoms, such as an unknown rash on your palms or a suspicious sore, helping to flag visual patterns that require medical attention. However, our artificial intelligence is only a screening aid, not a diagnostic tool. Syphilis requires a blood test or medical swab for an official diagnosis. Always consult a healthcare professional to confirm results and get the necessary antibiotic treatment.
Medical References
Information on this page is sourced from and verified against reputable medical resources:
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Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. The content on this page should not be used to diagnose or treat any health problem. Always consult with a qualified healthcare professional for proper medical evaluation, diagnosis, and treatment of your condition.