Syphilis; Symptoms, Causes, Diagnosis, and Treatment

What is Syphilis?

Syphilis is a sexually transmitted bacterial infection that is caused by the bacterium Treponema pallidum (T. pallidum). It can lead to neurological disorders, and even death if left untreated.

There are three stages of syphilis infection: Primary, secondary, and tertiary.

In the early stages, syphilis is treatable with antibiotics. Unless it is treated, syphilis will not resolve on its own without treatment. Note that syphilis infection can lie dormant for up to 30 years before returning as tertiary syphilis.

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A sore can appear on the vagina, mouth, anus, rectum, and lips. The infection can be spread during oral, anal, or vaginal sexual activity. Rarely, it can be passed on through kissing.

The first sign is a painless sore on the genitals, rectum, mouth, or skin surface. Some people do not notice the sore because it doesn’t hurt.

Syphilis can be spread through sexual contact with a syphilitic sore on the skin, and in mucous membranes. It cannot be spread by sharing surfaces like doorknobs or tables with an infected person.

A person who once had syphilis can still contract it again. Syphilis will not come back after treatment, but it can reappear with further exposure to the bacteria.

Pregnant women can pass syphilis to their unborn child, with possibly fatal consequences.

Causes of Syphilis

Syphilis is caused by T. pallidum bacteria. It occurs when the bacteria is transferred from one person to another during sexual activity.

Symptoms of Syphilis

Syphilis is classified into three stages with different symptoms linked with each stage.

There can be no symptoms for several years in some cases. Contagious stages include primary, secondary, and, occasionally, the early latent phase. Though tertiary syphilis has the most dangerous symptoms, it is not infectious.

Primary symptoms

In the primary stage, the symptoms of syphilis includes one or many round, painless, firm, and syphilitic sores called chancres. These sores are seen about 3 weeks after exposure.

Chancres disappear within 3 to 6 weeks, but, without treatment, the disease may progress to the next phase.

Secondary symptoms

Symptoms of secondary syphilis include:

  • A rash that does not itch and begins on the trunk and spreads to the whole body, including the palms of the hands and soles of the feet.
  • Sore throat
  • Rash may be rough, red, or reddish-brown in color
  • Fever
  • Weight loss
  • Fatigue
  • Wart-like sores that appear on the genitals, mouth, and anus
  • muscle aches
  • Patchy hair loss
  • swollen lymph nodes

These symptoms can resolve a few weeks after they appear, or they can return several times over a longer period. If left untreated at this secondary stage, syphilis can progress to the latent stage.

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Latent syphilis

A person may not experience any symptom in this latent phase which can last several years. After this, tertiary syphilis may develop, or the symptoms may never come back. However, the T. pallidum bacteria remain dormant in the body, and there is always a risk of recurrence.

Late or tertiary syphilis

Tertiary syphilis can occur 10 to 30 years after onset of the infection, normally after a period of latency, where there are no symptoms.

Symptoms include:

  • damage to the liver, joints, bones, blood vessels, and heart
  • soft tissue swellings that occur anywhere on the body


Neurosyphilis is a condition where the bacteria has spread to the nervous system. Though this condition is often associated with latent and tertiary syphilis, it can appear at any time after the primary stage.

It may be asymptomatic for a long time, or it can appear gradually.

Symptoms may include:

  • abnormal gait
  • confusion
  • weakness
  • dementia
  • numbness in the extremities
  • problems with concentration
  • headache or seizures
  • vision problems or vision loss

Congenital syphilis

Congenital syphilis can be deadly. Infection can transfer from a mother to her fetus through the placenta, and also during the birth process.

Symptoms in newborns includes:

  • fever
  • difficulty gaining weight
  • a rash of the genitals, anus, and mouth
  • small blisters on the hands and feet
  • saddle nose, in which the bridge of the nose is missing
  • watery nasal fluid

Symptoms in young children may include:

  • Hutchinson teeth, or abnormal, peg-shaped teeth
  • Hearing loss
  • vision loss
  • joint swelling
  • gray patches around the outer vagina and anus
  • bone pain
  • saber shins, a bone problem in the lower legs
  • scarring of the skin around the genitals, anus, and mouth

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Syphilis Risk factors

Those most at risk of contracting syphilis infection include:

  • sexually active people
  • those who have unprotected sex
  • men who have sex with men
  • those with HIV
  • people with numerous sexual partners

Diagnosing Syphilis

After asking about your symptoms and medical history, your doctor will carry out clinical tests to confirm syphilis. Tests may include:

  • Blood tests: To detect a current or past infection, as antibodies to the disease will be present for many years.
  • Bodily fluid: Fluid from a chancre during the primary or secondary stages can be assessed for the disease.
  • Cerebrospinal fluid: This may be collected through a spinal tap and examined to test for any impact on the nervous system.


Syphilis can be treated successfully in the early stages. It is essential to treat syphilis at the early stage with penicillin because long-term exposure to the disease can be deadly. During the primary, secondary, or late stages, patients will typically receive an intramuscular injection of Benzathine penicillin G.

The treatment strategy will depend on the symptoms and when the person was exposed. Tertiary syphilis will require multiple injections at weekly intervals.

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Neurosyphilis requires intravenous penicillin that would be given every 4 hours for 2 weeks to remove the bacteremia from the central nervous system (CNS).

Treating syphilis cannot reverse any damage that has already occurred. This is why it is essential to get treatment at the early stage to avoid complications.

Those with a penicillin allergy can sometimes use an alternative medication in the early stages. During pregnancy and in the tertiary stages, anyone with an allergy will be desensitized to penicillin to allow for treatment.

Following delivery, newborns who were exposed to syphilis in the womb should undergo antibiotic treatment.


You are expected to observe some preventive measures to reduce the risk of syphilis. These include:

  • Abstaining from sex
  • Use condom during sexual intercourse. Note that condom cannot protect you against sores on the body. abstaining from sex
  • Engage in long-term mutual monogamy with an uninfected partner
  • Use of a dental dam, or plastic square, during oral sex.
  • Avoid sharing sex toys
  • avoiding alcohol and drugs that could potentially lead to unsafe sexual practices

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Disclaimer: The content provided on is purely informative and educational in nature and should not be interpreted as medical advice. Please use the content only in consultation with an appropriate certified medical doctor or healthcare professional.


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