Syphilis - Exams and Tests

Exams and Tests

The first steps in diagnosing syphilis are discussing the history of your symptoms and sexual activities with a health professional and having a physical exam.

The diagnosis of syphilis is usually confirmed with one of several blood tests. This is especially true if no sores are present. If sores are present, a health professional may examine the fluid from one of the sores with a microscope to see whether syphilis bacteria are present (dark-field examination).

• A careful examination of the skin and mouth is performed to look for any rash or other abnormalities.
• For women, a pelvic exam is done to look for signs of syphilis. During the pelvic exam, your health professional will look for abnormal sores in the vagina or on the vulva, labia, rectal area, and inner thighs; these sores occur during the primary stage of syphilis.
• For pregnant women, the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) strongly recommend screening for syphilis because of the severe consequences of being pregnant while infected or having a child born with the disease (congenital syphilis). Screening should be done:¹
  • At the first prenatal visit for all pregnant women.
  • During the third trimester and again at delivery for pregnant women who have an increased risk of acquiring syphilis.
• For men, a genital exam is done to look for signs of syphilis.
• For newborns, the initial evaluation for congenital syphilis begins with a review of the mother's health and testing the mother for syphilis. The health professional will examine both mother and newborn for symptoms.

In the diagnosis of the primary and secondary stages of syphilis, lumbar puncture (spinal tap) is needed in rare cases. A lumbar puncture may be done in adults:

• If there is evidence of tertiary syphilis (such as aortic aneurysm, gumma, or iritis) or if neurosyphilis is suspected.
• If penicillin or another recommended antibiotic cannot be used for treatment in latent syphilis. If the appropriate antibiotic cannot be used, it is important to determine whether fluid from the spinal column and brain (cerebrospinal fluid) is infected because specific treatment methods are needed to effectively treat infected cerebrospinal fluid.
• Infected with HIV. Some experts recommend lumbar puncture in all HIV-infected people with syphilis.
• To check whether a person is cured of neurosyphilis.

In newborns and children, a lumbar puncture may be done if:

• There are signs of congenital syphilis.
• The child's mother had syphilis and she was not treated, was not treated adequately, or was treated after the 20th week of pregnancy.
• The child's mother was treated with an antibiotic other than penicillin.

Additional testing should be done to determine whether other sexually transmitted infections are present, especially:

• Chlamydia.
• Gonorrhea.
• Human immunodeficiency virus (HIV). People who have syphilis have a greater chance of being exposed to HIV.

The diagnosis of syphilis can be delayed or complicated because its symptoms are very similar to those of many other diseases and are sometimes not recognized. Syphilis has historically been referred to as "the great imitator."

Early Detection

Screening for syphilis is strongly recommended for pregnant women and for people who are at increased risk for the disease.

People at high risk of contracting syphilis include those who:²

• Have unprotected sex (do not use condoms or do not use them correctly). This risk is especially high among men who have sex with men.
• Have multiple sex partners, particularly if they live in an area of the country where syphilis is more common.
• Have a sex partner who has syphilis.
• Have sex with a partner who has multiple sex partners.
• Exchange money or drugs for sex (prostitution).
• Have human immunodeficiency virus (HIV) infection.

The CDC and the U.S. Preventive Services Task Force (USPSTF) strongly recommend that pregnant women be screened for syphilis because of the severe consequences of being pregnant while infected or having a child born with congenital syphilis. Screening should be done:¹

• At the first prenatal visit for all pregnant women.
• During the third trimester and again at delivery for pregnant women who have an increased risk of acquiring syphilis.