Syphilis refers to a sexually transmitted disease (STD) caused by Treponema pallidum bacteria. The infection starts as painless sores on the genitals, anus or mouth. It spreads from person to person via contact of skin or mucous membrane with these sores. Syphilis occurs in primary, secondary, latent and tertiary/late stages. Primary and secondary stages are very contagious, but late and latent phases are not. The stages may be separated by long periods in which T. pallidum bacteria remain inactive.


Syphilis can be of two types:

  • Acquired, if the bacterial infection spreads by sexual contact or non-sexually by skin contact. It is the more common of the two types.
  • Congenital, if the infection spreads from mother to the newborn through the placenta or during birth.


In some cases, syphilis infection might not produce any symptoms for years. Symptoms, when present, vary with the different stages.

Primary syphilis

  • Appearance of a small sore called a chancre at the point of entry of bacteria about 3 weeks after exposure.
  • Healing of the chancre within 6 weeks.
  • Swelling of lymph nodes.

Secondary syphilis

  • Appearance of non-itchy rash.
  • Spreading of rash over the whole body including palms and soles.
  • Presence of wart-like sores in the mouth or on genitals.
  • Fever.
  • Sore throat.
  • Loss of appetite.
  • Bone pain.
  • Muscle aches.
  • Swollen lymph nodes.

Latent syphilis

Latent (hidden) stage does not present any symptoms. The stage can last for years.

Tertiary or late syphilis

  • Damage to organs throughout the body.
  • Dementia.
  • Deformities.
  • Blindness.
  • Deafness.

Congenital syphilis

Symptoms of congenital syphilis, if present, include the following:

  • Rash on the palms and the soles (early symptoms)
  • Deafness and deformities in eye, teeth and nose bone (late symptoms)

Syphilis infection is severe in HIV patients. These patients often develop complications in organs like the eyes and brain.


Syphilis is caused by T. pallidum bacteria. Transmission of bacterial infection most commonly happens during sexual activity upon contacting an infected person’s sore. The bacteria enter the body through small cuts or scratches in the skin or mucous membranes. After entering the body, the bacteria reach the nearby lymph nodes within few hours, and infection rapidly spreads throughout the body. In few cases, syphilis may spread through direct contact with an active sore (e.g., during kissing) or through an infected mother to the baby. Engaging in unprotected sex and having sex with multiple partners increase the risk of catching syphilis.


Syphilis is curable if it is diagnosed and treated in its early stages. The antibiotic penicillin is given to kill the bacteria in all stages of syphilis and during pregnancy. Sex partners of infected people should also get treated. Ceftriaxone antibiotic is given to patients who are allergic to penicillin.

Many patients show a reaction to penicillin within 6 to 12 hours of receiving it. Called Jarisch-Herxheimer reaction (JHR), this effect may show symptoms like discomfort, fever, sweating, headache, or anxiety. Jarisch-Herxheimer reaction goes away on its own within 24 hours. Patients with syphilis should also be tested for other sexually transmitted infections, including HIV, and treatment of these diseases may also be necessary.

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