Latent syphilis is defined as having serologic proof of infection without signs or symptoms of disease.  Latent syphilis is further described as either early or late. Early latent syphilis is defined as having syphilis for two years or less from the time of initial infection without signs or symptoms of disease. Late latent syphilis is infection for greater than two years but without clinical evidence of disease. The distinction is important for both therapy and risk for transmission. In the real world, the timing of infection is often not known and should be presumed to be late for the purpose of therapy. Early latent syphilis may be treated with a single intramuscular injection of a long-acting penicillin. Late latent syphilis requires three weekly injections. For infectiousness late latent syphilis is not considered as contagious as early latent syphilis. Fifty percent of those infected with latent syphilis will progress into late stage (tertiary) syphilis, 25% will stay in the latent stage, and 25% will make a full recovery.

Secondary syphilis occurs approximately 1–6 months (commonly 6 to 8 weeks) after the primary infection. There are many different manifestations of secondary disease. There may be a symmetrical reddish-pink non-itchy rash on the trunk and extremities.  The rash can involve the palms of the hands and the soles of the feet. In moist areas of 
the body (usually vulva or scrotum), the rash becomes flat, broad, whitish, wart-like lesions known as condyloma latum. Mucous patches may also appear on the genitals or in the mouth. All of these lesions are infectious and harbor active treponeme organisms. A patient with syphilis is most
 contagious when he or she has secondary syphilis. Other symptoms common at this stage include fever, sore throat, malaise, weight loss, headache, meningismus and enlarged lymph nodes. Rare manifestations include an acute meningitis  that occurs in about 2% of patients, hepatitis, renal disease, hypertrophic gastritis, patchy proctitis, ulcerative colitis, rectosigmoid  mass, arthritis, periostitis, optic neuritis, interstitial keratitis, iritis and uveitis.


 Typical presentation of secondary syphilis rash on the palms of the hands and usually also seen on soles of feet.

Primary syphilis is typically acquired via direct sexual contact with the infectious lesions of a person with syphilis.  Approximately 10–90 days after the initial exposure (average 21 days) a skin lesion appears at the point of contact, which is usually the genitalia, but can be anywhere on the body. This lesion, called a chancre, is a firm, painless skin ulceration localized at the point of initial exposure to the spirochete, often on the penis, vagina  or rectum. In rare circumstances, there may be multiple lesions present, although it is typical that only one lesion is seen. The lesion may persist for 4 to 6 weeks and usually heals spontaneously. Local lymph node swelling can occur. During the initial incubation period, individuals are otherwise asymptomatic. As a result, many patients do not seek medical care immediately.

Primary chancre  of syphilis on the hand. Unlike some kinds of sexually transmitted infections, syphilis infections are not limited to the genitals, and can be transmitted through non-sexual contact.

Syphilis is a sexually transmitted disease caused by the spirochetal bacterium Treponemapallidum subspecies pallidum. The route of transmission of syphilis is almost always through sexual contact, although there are examples of congenital syphilis via transmission from mother to child in utero or at birth.

The signs and symptoms of syphilis are numerous; before the advent of serological testing, precise diagnosis was very difficult. In fact, the disease was dubbed the "Great Imitator" because it was often confused with other diseases, particularly in its tertiary stage.

Syphilis can generally be treated with antibiotics, including penicillin. If left untreated, syphilis can damage the heart, aorta, brain, eyes, and bones. In some cases these effects can be fatal.