Infectious Syphilis: The Return of an Epidemic

Robert B. Stroube, MD, MPH


May 12, 2008

In This Article

Infectious Syphilis: From Past to Present

Syphilis is a sexually transmitted disease that is caused by Treponema pallidum, a spirochete, and has often been called the "great imitator" because many of its signs and symptoms are indistinguishable from those of other diseases. Disease transmission results from direct contact with infectious exudates from moist, early lesions of the skin and mucous membranes of infected people during sexual contact. Exposure can occur from oral, anal, or vaginal intercourse. Syphilis is communicable when the moist mucocutaneous lesions of primary or secondary syphilis are present. Because syphilis is an ulcerative genital disease, it can facilitate the transmission of the human immunodeficiency virus (HIV), putting people with syphilis at greater risk for HIV infection.[1]

Primary syphilis is the first stage of the disease with the appearance of a chancre at the spot where the spirochete entered the body. A chancre is usually a firm, round, small, painless ulcer that appears in 10-90 days after exposure, on average 3 weeks after exposure. It lasts 3-6 weeks and heals spontaneously without treatment. It is often unrecognized in rectal, cervical, or oral lesions. This is the stage that is most infectious.

Without treatment, primary syphilis will progress to secondary syphilis, which is characterized by a skin rash and mucous membrane lesions. The skin rash usually occurs within 4 weeks after the chancre has healed and is typically nonpruritic, rough, with reddish-brown spots on the palms of the hands and the bottoms of the feet. A symmetric maculopapular rash involving the palms and soles with lymphadenopathy is classic for syphilis. Constitutional signs and symptoms, such as headache, myalgias, sore throat, patchy hair loss, fatigue, weight loss, fever, or other types of rashes may occur. These will spontaneously resolve over a period of weeks, even if not treated. Transmission can occur at this stage if there are moist mucocutaneous lesions. If untreated, secondary syphilis will evolve into latent syphilis, in which there are no signs or symptoms, but the person will be seropositive for syphilis.[2]

Congenital syphilis occurs when the fetus is infected in utero and with high frequency in pregnant women who have untreated early syphilis. This infection often results in abortion or stillbirth. Infant death may occur because of preterm birth due to low birth weight or generalized disease. Additionally, there can be late manifestations, such as central nervous system involvement.


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