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

Key Facts

Most syphilis infections are asymptomatic or go unrecognized.
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.