Fast Five Quiz: Sexually Transmitted Infections

Michael Stuart Bronze, MD


February 28, 2022

Physicians must keep a high index of suspicion for the diagnosis of syphilis because the manifestations of syphilis (particularly advanced syphilis) are nonspecific and may masquerade as many other diseases. Rigorous attention to the time course of symptoms is required for proper staging.

Primary syphilis occurs 10-90 days after contact with an infected individual. It manifests mainly on the glans penis in males and on the vulva or cervix in females. Secondary syphilis usually presents with a cutaneous eruption within 2-10 weeks after the primary chancre and is most florid 3-4 months after infection. The eruption may be subtle.

The CDC recommends that all pregnant women be screened for syphilis at the first prenatal visit. Retesting at 28 week's gestation and delivery is recommended for women who are at high risk. This includes women living in areas with high syphilis morbidity and those who are at increased risk for acquisition (eg, using drugs, concerning sexual history).

Penicillin remains the mainstay of treatment and the standard by which other modes of therapy are judged. The following regimens are recommended for penicillin treatment:

  • Primary or secondary syphilis: benzathine penicillin G (2.4 million units IM in a single dose)

  • Early latent syphilis: benzathine penicillin G (2.4 million units IM in a single dose)

  • Late latent syphilis or latent syphilis of unknown duration: benzathine penicillin G (7.2 million units total, administered as three doses of 2.4 million units IM each at 1-week intervals)

  • Pregnancy: treatment appropriate to the stage of syphilis

Alternative therapies in patients with syphilis who are unable to receive penicillin include doxycycline (100 mg orally twice daily for 14 days) or ceftriaxone (1-2 g IM or intravenously daily for 10-14 days) or tetracycline (100 mg orally four times daily for 14 days). Although azithromycin is effective, resistance is increasing in the United States; therefore, azithromycin should be used only in areas of low resistance or in early syphilis with close clinical follow-up.

Learn more about syphilis.

This Fast Five Quiz was excerpted and adapted from the Medscape articles Trichomoniasis, Chlamydia (Chlamydial Genitourinary Infections), Gonorrhea, Human Papillomavirus (HPV), and Syphilis.

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