Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. Syphilis can cause long-term complications and/or death if not adequately treated. Syphilis can also be spread from a mother to her unborn baby.

Syphilis is curable if it is found and treated early.

How common is syphilis in Montana?

Syphilis is spreading faster in Montana than it has in decades.  During 2022, there were 603 cases of syphilis (all stages).  Syphilis rates are increasing in women in recent years.  Congenital syphilis is a concern in the United States and in Montana.  Preliminary 2022 data shows 15 cases of congenital syphilis in Montana.

What you need to know about syphilis

There are four stages of syphilis (primary, secondary, latent, and tertiary).  Each stage has different signs and symptoms.

Primary Stage

During the primary stage of syphilis, you may notice a single sore or multiple sores.  The sore is the location where syphilis entered your body.  These sores usually occur in, on, or around the:

  • Penis
  • Vagina
  • Anus
  • Rectum
  • Lips or in the mouth.

Sores are usually (but not always) firm, round, and painless.  Because the sore is painless, you may not notice it.  The sore usually lasts 3 to 6 weeks and heals regardless of whether you receive treatment.  Even after the sore goes away, you must still receive treatment.  This will stop your infection from moving to the secondary stage.

Secondary Stage

During the secondary stage, you may have skin rashes and/or sores in your mouth, vagina, or anus.  This stage usually starts with a rash on one of more areas of your body.  The rash can show up when your primary sore is healing or several weeks after the sore has healed.  The rash can be on the palms of your hands and/or bottoms of your feet and look

  • Rough
  • Red or
  • Reddish brown.

The rash usually won’t itch, and it is sometimes so faint that you won’t notice it.  Other symptoms may include:

  • Fever
  • Swollen lymph nodes
  • Sore throat
  • Patchy hair loss
  • Headaches
  • Weight loss
  • Muscle aches and
  • Fatigue (feeling very tired).

The symptoms from this stage will go away whether you receive treatment.  Without the right treatment, your infection will move to the latent and possibly tertiary stages of syphilis.

Latent Stage

The latent stage of syphilis is a period when there are no visible signs or symptoms.  Without treatment, you can continue to have syphilis in your body for years.

Tertiary Stage

Most people with untreated syphilis do not develop tertiary syphilis.  However, when it does happen, it can affect many different organ systems.  These include the heart and blood vessels, and the brain and nervous system.  Tertiary syphilis is very serious and would occur 10-30 years after your infection began.  In tertiary syphilis, the disease damages your internal organs and can result in death.  A healthcare provider can usually diagnose tertiary syphilis with the help of multiple tests.


Without treatment, syphilis can spread to the brain and nervous system, the eye, or the ear.  It can cause severe headache, pain, changes in vision, hearing loss, ringing in the ears, and dizziness or vertigo.

The average time between infection with syphilis and the start of the first symptom is 21 days, but can range from 10 days to 90 days. 

When a pregnant person has syphilis, the infection can spread to their unborn baby.  All pregnant people should receive testing for syphilis at the first prenatal visit.  Some people will need testing again during the third trimester (28 weeks gestation) and at delivery.  This includes people who live in areas of high syphilis rates or are at risk for getting syphilis during pregnancy.

Risk factors for getting syphilis during pregnancy include:

  • Sex with multiple partners,
  • Sex in conjunction with drug use or transactional sex,
  • Late entry to prenatal care (i.e. first visit during the second trimester or later) or no prenatal care,
  • Methamphetamine or heroin use,
  • Incarceration of the pregnant person or their partner,
  • Unstable housing or homelessness.


Any person who delivers a stillborn infant after 20 weeks’ gestation should also receive testing for syphilis.

Depending on how long a pregnant person has had syphilis, they may be at high risk of having a stillbirth. The baby could also die shortly after birth.  Untreated syphilis in pregnant people results in infant death in up to 40% of cases.

A baby born alive with syphilis may not have any signs or symptoms of disease.  However, if treatment is not immediate, the baby may develop serious problems within a few weeks.  Babies who do not receive treatment may have developmental delays, seizures, or die.  Babies born to those who test positive for syphilis during pregnancy should receive congenital syphilis screening and a thorough exam.

Most of the time, healthcare providers will use a blood test to test for syphilis.

Any person with signs or symptoms suggestive of syphilis should receive a test for syphilis.  Also, anyone with an oral, anal, or vaginal sex partner who receives a recent syphilis diagnosis should receive testing.

Some people should receive testing (screening) for syphilis even if they do not have symptoms or know of a sex partner who has syphilis.  Anyone who is sexually active should discuss their risk factors with a healthcare provider.  They should ask their healthcare provider about testing for syphilis or other sexually transmitted infections.

In addition, healthcare providers should routinely test for syphilis in people who

  • Are pregnant,
  • Are sexually active MSM,
  • Are living with HIV and are sexually active, and
  • Are taking PrEP for HIV prevention.

Syphilis can be cured with the right antibiotics from your healthcare provider.  It is important to follow your healthcare provider’s instructions and keep all follow up appointments.

How can someone prevent syphilis?

You can reduce your risk of getting syphilis by avoiding unprotected sex (sex without a condom) with someone who may have syphilis.  Some ways to protect yourself include only having sex with a person who has been tested for syphilis and does not have syphilis, and by using latex condoms the right way every time you have sex. For more information, please click here.