If untreated, syphilis can progress through the primary, secondary, latent, and tertiary phases of development. We provide a brief description of each phase in the following paragraphs.

Primary Syphilis In its initial or primary phase, syphilis is generally manifested in the form of a single, painless sore called a chancre (SHANG-kur), which usually appears

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about 3 weeks after initial infection at the site where the spirochete organism entered the body (see I Figure 15.2). In women this sore most commonly appears on the inner vaginal walls or cervix. It can also appear on the external genitals, particularly the labia. In men the chancre most often occurs on the glans of the penis, but it can also show up on the penile shaft or on the scrotum. Although most chancres are genital, the sores can occur in the mouth or rectum or on the anus or breast. People who have had oral sex with an infected individual might develop a sore on the lips or tongue. Anal intercourse can result in chancres appearing in the rectum or around the anus.

Since the chancre is typically painless, it often goes undiscovered when it occurs on internal structures, such as the rectum, vagina, or cervix. (Occasionally, chancres may be painful, and they may occur in multiple sites.) Even when the chancre is noticed, some people do not seek treatment. Unfortunately (from the long-term perspective), the chancre generally heals without treatment 3 to 6 weeks after it first appears. For the next few weeks, the infected person usually has no symptoms but can infect an unsuspecting partner. After about 6 weeks (although sometimes after as little as 2 weeks or as many as 6 months), the infection often progresses to the secondary stage in people with untreated primary syphilis.

Secondary Syphilis In the secondary phase, which usually emerges 2 to 8 weeks after exposure, a skin rash appears on the body, often on the palms of the hands and soles of the feet (see I Figure 15.3). The rash can vary from barely noticeable to severe, with raised bumps that have a rubbery, hard consistency. Although the rash may look terrible, it typically does not hurt or itch. Besides a generalized rash, a person may experience flulike symptoms, such as fever, swollen lymph glands, fatigue, weight loss, and joint or bone pain. Even when not treated, these symptoms usually subside within a few weeks. Rather than being eliminated, however, the infection can then enter the potentially more dangerous latent phase (Centers for Disease Control, 2009e).

Latent Syphilis The latent stage can last for several years, during which time there may be no observable symptoms (Centers for Disease Control, 2009e). Nevertheless, the infecting organisms continue to multiply, preparing for the final stage of syphilitic infection. After 1 year of the latent stage, the infected individual is no longer contagious to sexual partners. However, a pregnant woman with syphilis in any stage can pass the infection to her fetus.

Tertiary Syphilis Approximately 15% of individuals who do not obtain effective treat­ment during the first three stages of syphilis enter the tertiary stage later in life (Centers

Sexually Transmitted Infections

for Disease Control, 2009e). The final manifestations of syphilis can be severe, often resulting in death. They usually occur anywhere from 10 to 20 years after initial infection and include such conditions as heart failure, blindness, ruptured blood vessels, paralysis, skin ulcers, liver damage, and severe mental disturbance (Centers for Disease Control, 2009e). Treat­ment even at this late stage can be beneficial.

Genital sores (chancres) associated with the primary phase of syphi­lis infections increase the possibility of either transmitting or acquiring HIV infection through sexual activity. It is estimated that there is a two – to fivefold increased risk of becoming infected with HIV if exposed to this infectious virus when syphilitic sores are present (Centers for Dis­ease Control, 2009e). Any sores, ulcers, or breaks in the skin (conditions that often accompany STIs) increase the possibility of either transmitting or becoming infected with HIV. Ulcerative sores bleed easily (blood is a major reservoir for HIV), and when they come into contact with genital, oral, or rectal mucosa during sexual activity there is a resulting increase in both the infectiousness of and susceptibility to HIV.

Treatment

Primary, secondary, or latent syphilis of less than 1 year’s duration can be effectively treated with intramuscular injections of benzathine penicillin G. People who are allergic to penicillin can be treated with doxycycline, tetracycline, or ceftriaxone. Syphilis of more than 1 year’s duration is treated with intramuscular injections of benzathine penicillin G once a week for 3 successive weeks. The CDC recommends follow-up at 6 and 12 months after initial diagnosis to determine the effectiveness of treat­ment. Recent research reveals significant risk factors for repeat syphilis infection, especially among MSM (Cohen et al., 2012).

All sex partners who have been exposed to a person with infectious syphilis should be tested and treated if necessary.