Symptoms of syphilis in adults vary by stage:

Primary Stage

During the first (primary) stage of syphilis, you may notice a single sore or multiple sores. The sore is the location where syphilis entered your body. Sores are usually (but not always) firm, round, and painless. Because the sore is painless, it can easily go unnoticed. The sore usually lasts 3 to 6 weeks and heals regardless of whether or not 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 mucous membrane lesions. Mucous membrane lesions are sores in your mouth, vagina, or anus. This stage usually starts with a rash on one or 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 look like rough, red, or reddish brown spots on the palms of your hands and/or the bottoms of your feet. The rash usually won’t itch and it is sometimes so faint that you won’t notice it. Other symptoms you may have can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue (feeling very tired). The symptoms from this stage will go away whether or not you receive treatment. Without the right treatment, your infection will move to the latent and possibly tertiary stages of syphilis.

Secondary rash of syphilis on torso

The latent stage of syphilis is a period of time when there are no visible signs or symptoms of syphilis. If you do not receive treatment, you can continue to have syphilis in your body for years without any signs or symptoms.

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.

Neurosyphilis and Ocular Syphilis

Without treatment, syphilis can spread to the brain and nervous system (neurosyphilis) or to the eye (ocular syphilis). This can happen during any of the stages described above.

Symptoms of neurosyphilis include

• severe headache;
• difficulty coordinating muscle movements;
• paralysis (not able to move certain parts of your body);
• numbness; and
• dementia (mental disorder).

Symptoms of ocular syphilis include changes in your vision and even blindness.