Syphilis is a sexually transmitted infection (STI) that can cause serious health problems without treatment. Infection develops in stages (primary, secondary, latent, and tertiary). Each stage can have different signs and symptoms.

Risks

• spreads through sex (vaginal, oral, or anal) without a condom with a partner who has the infection
• pregnant woman with syphiis can give the infection to her unborn baby

Symptoms

Primary Stage:

• sores at the location where syphilis entered the body: genitals, anus, rectum and lips/mouth
• sores are usually (but not always) firm, round and painless
• sores last 3-6 weeks and heal with or without treatment, but that doesn’t mean the syphilis is gone; treatment is still necessary to avoid moving into the secondary stage

Secondary Stage:

• skin rashes and/or sores in the mouth, vagina, or anus
• rash can show up when the primary sore is healing or several weeks after the sore has healed, and can be on the palms or the hands and/or the bottoms of the feet
• rash can look rough, red or reddish-brown
• rash usually will not itch and may be so faint that you don’t notice it
• also possible: fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue (feeling very tired)
• symptoms from this stage will go away with or without treatment
• without the right treatment, the infection will move to the latent and possibly tertiary stages of syphilis

Latent Stage:

• 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
• when it does happen, it can affect many different organ systems including 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
• damages your internal organs and can result in death

Testing

• detected by a blood test or from testing fluid from a syphilis sore

Treatment

• treated and cured with antibiotics in the early stages
• repeat infection is possible
• left untreated, it can cause serious and permanent health problems

Source and more info: CDC – Syphilis