Merck Manual

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Reviewed/Revised Apr 2023
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What is syphilis?

  • Syphilis spreads easily through anal, oral, or vaginal sex with an infected person

  • A pregnant woman can spread syphilis to her baby

  • Syphilis has 3 stages that get progressively worse

  • Doctors treat syphilis with penicillin

What are the 3 stages of syphilis?

Stage 1: Syphilis starts in the part of your body that was exposed to your sex partner's body fluids. For example, if you had vaginal sex, syphilis may start on your penis (if you're a man) or in or near your vagina (if you're a woman).

Stage 2: Syphilis spreads into your blood and infects your skin.

Stage 3: Syphilis spreads throughout your body. Any body part can be infected by syphilis but particularly your heart, blood vessels, brain, and spinal cord.

There is often a time gap between stage 2 and stage 3. This gap is called the latent period. During the latent period, people feel well and usually can't pass syphilis to other people. Sometimes syphilis stops after stage 2. However, about 1 out of 3 people with an untreated syphilis infection go on to stage 3.

What are the symptoms of syphilis?

Symptoms are different in each stage of syphilis.

Symptoms of stage 1 (primary) syphilis

  • A small, red, raised area at the infection site, such as your penis, vagina, rectum (where poop is stored), or lips

  • The small red area turns into a painless, open sore that's hard and doesn’t bleed

  • You may not notice the sore because it doesn't cause many symptoms

  • 3 to 12 weeks later, the sore heals and you’ll feel healthy

If not treated, syphilis will move to stage 2 because the infection spreads in your blood.

Symptoms of stage 2 (secondary) syphilis

  • A painless rash on your body that doesn't itch—unlike most other rashes, the rash from syphilis often appears on the palms of your hands or soles of your feet

  • Raised, flat, smooth warts may also form on the moist areas around your mouth, armpits, sex parts, and anus (where poop comes out)

  • Fever

  • Feeling weak and tired all over

  • Feeling less hungry than usual

  • Swollen lymph nodes

The warts are full of syphilis germs. The germs can spread to people who touch the warts.

Stage 2 symptoms eventually go away. But they can cause problems with other parts of your body and organs, such as your liver, kidneys, and eyes. If not treated, you may not have any more symptoms. However, about 1 out of 3 people with syphilis will move to stage 3.

Symptoms of stage 3 (tertiary or late) syphilis

Symptoms may affect your skin, blood vessels, heart, brain, or spinal cord.

Skin problems can include:

  • Soft, rubbery bumps on your skin, such as your scalp and face (the bumps can also be inside your body, such as on your liver or bones)

  • The bumps turn into open sores and kill the tissue around them

  • The bumps slowly heal and leave scars

Blood vessel problems usually involve the big artery (aorta) that comes out of the heart and carries blood to the body. The aorta may weaken and widen. Sometimes the weakened aorta splits open (ruptures), which can be fatal. An aorta problem causes:

  • Chest pain

  • Chest pain

  • Trouble breathing

  • Heart attack

Brain problems usually don't appear for 15 to 20 years. Symptoms include:

  • Headache

  • Stiff neck

  • Changes in your mood or behavior

  • Trouble thinking clearly

Spinal cord infection makes it hard to control your muscles. You might have:

  • Loss of feeling in your feet

  • Difficulty walking

  • Pain and in your back, legs, or arms

  • Weakness of your arms or legs

How can doctors tell if I have syphilis?

How do doctors treat syphilis?

Doctors will:

  • Give you a shot of penicillin into one of your muscles, usually your rear end

  • Give you extra doses of penicillin based on your stage and symptoms

  • Tell you to avoid having sex until you have finished treatment

  • Test and treat your sex partners for syphilis

  • Do blood tests and exams to make sure treatment worked

People who are allergic to penicillin may be given other antibiotics.

Sometimes when the penicillin kills the syphilis germs, your body reacts to all the dead and dying germs. This reaction usually happens within the first 12 hours. You may have fever, headache, muscle aches, and a rash. This reaction is uncomfortable but not dangerous. It goes away within 24 hours. This reaction isn't due to an allergy to penicillin.

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