Syphilis: Stages, Symptoms, and How to Protect Yourself

Syphilis is one of the most consequential STDs currently circulating in the United States — not because it is difficult to treat, but because it is difficult to recognize. It progresses through stages, each with different presentations, and the stages that are most infectious are also the ones most likely to go unnoticed. The result is a treatable infection that kills when it isn’t caught.

Quick answer: Syphilis is a bacterial infection that progresses through four stages: primary (painless sore), secondary (rash, flu-like illness), latent (no symptoms), and tertiary (organ damage). It is curable with penicillin at any stage, but damage from tertiary syphilis cannot be reversed. US syphilis rates have more than doubled since 2018. Annual testing is recommended for all sexually active people with new or multiple partners. Same-day testing available in Los Angeles, Houston, New York City, Miami, and Chicago.

The Four Stages of Syphilis

Primary syphilis (weeks 1–6 after exposure): A single, firm, painless sore — the chancre — appears at the site where Treponema pallidum entered the body: the genitals, anus, lips, or throat. It heals on its own within 3–6 weeks regardless of treatment. This spontaneous healing is deceptive — the infection has not resolved, it has progressed.

Secondary syphilis (weeks 6–24): Bacteria circulate systemically. The classic presentation is a diffuse rash that characteristically involves the palms of the hands and soles of the feet — a pattern almost unique to syphilis. Accompanying symptoms include fever, swollen lymph nodes, sore throat, patchy hair loss, and fatigue. Highly infectious mucous patches may appear in the mouth, vagina, or anus. Secondary syphilis also resolves spontaneously without treatment.

Latent syphilis: No symptoms. The infection is dormant but active. Early latent (within 12 months of infection) may still cause secondary relapses. Late latent (beyond 12 months) is less infectious to sexual partners but can still be transmitted from mother to foetus. Latent syphilis can persist for years or decades.

Tertiary syphilis: Develops in approximately 15–30% of untreated cases. Gummatous disease destroys tissue in skin, bone, and organs. Cardiovascular syphilis causes aortitis, aneurysm, and valve incompetence. Neurosyphilis — invasion of the central nervous system — causes dementia, personality change, stroke, and blindness. Tertiary complications are irreversible even after cure of the infection.

Why Syphilis Is So Often Missed

The primary chancre is painless and may appear in an internal or non-visible location — inside the vagina, rectum, under the foreskin, or on the cervix. Many patients never notice it. The secondary rash is frequently attributed to allergies, eczema, or viral illness. Latent syphilis has no symptoms at all. Clinicians who don’t consider syphilis in the differential miss all three stages until complications develop.

Congenital syphilis — transmission from an infected mother to her foetus — causes stillbirth, severe organ damage, and developmental problems. Every case is preventable with routine prenatal syphilis screening and treatment. The US congenital syphilis rate rose by over 750% between 2012 and 2022, reflecting failures of prenatal care access in underserved populations.

Testing and Treatment

Syphilis is diagnosed by blood test. The standard approach uses a treponemal test (TPPA, TPHA, or FTA-ABS) as initial screening, confirmed by a non-treponemal test (RPR or VDRL) that also monitors treatment response. The window period is 3–6 weeks after exposure.

Treatment is penicillin G: a single intramuscular injection for primary, secondary, and early latent syphilis; three weekly injections for late latent; intravenous penicillin for neurosyphilis. Treatment is curative at any stage but cannot reverse structural damage already caused by tertiary disease.

When to Seek Urgent Care

• Painless sore on genitals, anus, or mouth: test within 24 hours — don’t wait for it to resolve on its own.

• Rash on palms or soles with flu-like illness: same-day evaluation for secondary syphilis.

• Eye symptoms (pain, redness, vision change) with known or suspected syphilis: emergency evaluation — ocular syphilis can cause permanent blindness within days.

• Neurological symptoms in someone with syphilis history: emergency evaluation for neurosyphilis.

• Pregnant and syphilis-positive: contact your OB same day — treatment timing determines foetal outcome.

Frequently Asked Questions

How do I know if I have syphilis if I have no symptoms?

You don’t — which is why testing is necessary. Latent syphilis has no symptoms by definition. The only way to know is a blood test. Annual syphilis screening is recommended for MSM, pregnant women (at first prenatal visit and again in the third trimester), and anyone with new or multiple sexual partners.

Can syphilis go away without treatment?

The visible symptoms of primary and secondary syphilis resolve spontaneously. The infection does not. Without treatment, syphilis progresses to latent stage and eventually tertiary disease in a significant proportion of untreated people. Spontaneous resolution of the chancre or rash is not a sign that the infection has cleared.

Is syphilis common?

Yes, and rates are rising. US syphilis cases have more than doubled since 2018. MSM account for a significant proportion of cases, but rates are rising in heterosexual men and women as well. Congenital syphilis is at a 30-year high. Syphilis is not a historical disease — it is an active and growing epidemic.

Can you get syphilis from oral sex?

Yes. Syphilis transmits efficiently through oral contact with an active sore. Oral chancres (on the lips or tongue) are highly infectious and can be transmitted through kissing or oral sex. Secondary syphilis mucous patches in the mouth are also transmissible through oral contact.

Related: STD Testing: What You Need to Know · STDs With No Symptoms · Syphilis and Vision · Syphilis and Heart Disease · Get tested today →