Syphilis: The 4 Stages, Symptoms, Risks & Effective Treatments

Key Facts

• Syphilis progresses through four distinct stages, each presenting different symptoms and transmission risks—yet most infections remain asymptomatic or go unrecognized. This sexually transmitted infection affects 8 million adults globally each year, and without proper antibiotic treatment, can cause severe complications including blindness, paralysis, and death.

• In 2022, the WHO estimated 8 million new syphilis infections among adults aged 15–49.

• Untreated syphilis during pregnancy can result in 50–80% of adverse birth outcomes.

• Gay and bisexual men are among the most affected populations globally.

What Is Syphilis?

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It’s known for progressing through four distinct stages—each with its own symptoms and health risks. Although syphilis is treatable with antibiotics, delayed or incorrect treatment can lead to severe complications, including death.

How Syphilis Is Transmitted

Syphilis spreads through direct contact with syphilitic sores, which typically appear on the genitals, anus, lips, or mouth. Transmission occurs primarily through vaginal, anal, or oral sex, and the infection can also be passed from pregnant individuals to their babies, resulting in congenital syphilis.

Common Transmission Routes:

• Sexual contact with an infected person (vaginal, anal, or oral)

• Skin-to-skin contact with open syphilitic sores

• Mother-to-child transmission during pregnancy or childbirth

Who’s at Higher Risk?

• Individuals with multiple sexual partners

• People who do not use condoms

• Those already diagnosed with other STIs

Recognizing the Stages of Syphilis

Syphilis develops in four progressive stages, and symptoms may vary or disappear between phases.

Primary Syphilis

• A single, painless sore (chancre) appears at the infection site

• Typically heals in 3–6 weeks, but infection remains

• The chancre may go unnoticed, especially if internal

Secondary Syphilis

• Appears weeks after the chancre heals

• Common symptoms:

  • Rash (especially on palms or soles)

  • Swollen lymph nodes

  • Fever

  • Sore throat

  • Patchy hair loss

  • Fatigue

• Highly infectious during this stage

Latent Syphilis

• No visible symptoms

• Bacteria remain in the body

• May last for years

• Early latent syphilis (<1 year) is still potentially infectious

• Late latent syphilis is typically non-infectious

Tertiary Syphilis

• Can develop 10–30 years after infection

• Affects organs such as the heart, brain, liver, and eyes

• May lead to paralysis, blindness, dementia, or death

What Is Neurosyphilis?

Neurosyphilis is a severe form of the infection where T. pallidum affects the central nervous system. It can occur at any stage of syphilis.

Symptoms of Neurosyphilis:

• Headaches and neck stiffness (signs of meningitis)

• Vision or hearing loss (ocular or otosyphilis)

• Cognitive issues, personality changes (general paresis)

• Muscle weakness or coordination problems (tabes dorsalis)

• Stroke-like episodes (meningovascular syphilis)

How to Prevent Syphilis

Protecting yourself and others starts with awareness and proactive prevention.

Tips to Reduce Your Risk:

• Use condoms or dental dams during sex

• Get regular STI screenings—especially if you have multiple partners

• Avoid sex if you or your partner have unexplained sores or rashes

• Communicate openly about STI status and sexual health

• Engage with public health campaigns and educational resources

Treating Syphilis: What You Need to Know

Syphilis is curable with antibiotics. The type and duration of treatment depend on the stage of infection.

Standard Treatments:

• Primary or secondary syphilis: Single intramuscular injection of benzathine penicillin G

• Late latent syphilis: Weekly injections for 3 weeks

• Neurosyphilis: IV penicillin for 10–14 days

Penicillin Alternatives:

• Doxycycline

• Azithromycin

• Ceftriaxone (used with caution; effectiveness may vary by stage)

Why Early Diagnosis Is Crucial

If left untreated, syphilis can:

• Cause irreversible organ damage

• Lead to blindness, paralysis, or mental health decline

• Be transmitted to babies during pregnancy

Getting tested early can prevent complications and stop the spread.

Frequently Asked Questions (FAQs)

How long does it take for syphilis symptoms to appear?

Most people develop symptoms within 3 weeks, but it can take up to 90 days.

Can syphilis go away on its own?

No. Symptoms may fade temporarily, but the infection remains active without proper treatment.

Is syphilis contagious during all stages?

Syphilis is most contagious during the primary and secondary stages. Latent syphilis is less likely to spread, but it can still pose a risk during pregnancy.

Key Takeaways

• Syphilis progresses in 4 stages, each with specific symptoms

• Early detection and timely antibiotic treatment are essential

• Practice safe sex and get tested regularly to reduce your risk

• Untreated syphilis can have life-altering consequences

Check out our Medheads podcast: Syphilis – The STI That Can Eat Your Brain