Diagnosis
In the ED, where patients such as the one in our case are often lost to follow-up, and consistent infectious disease and primary care follow-up is unavailable, prompt treatment based on history and physical examination alone is recommended. Patients should be tested for syphilis, as well as other STIs including chlamydia, gonorrhea, hepatitis, and HIV as an outpatient. In addition, any partners with whom the patient has had sexual contact within the last 90 days should also undergo STI testing; sexual partners from over 90 days should be notified of the patient’s status and evaluated with testing as indicated.4 All positive test results should be reported to the Centers for Disease Control and Prevention (CDC).5
Nontreponemal and Treponemal Testing
For patients with clinical signs and symptoms of syphilis, recommended laboratory evaluation includes both nontreponemal and treponemal testing. Nontreponemal tests include RPR, venereal disease research laboratory test, and toluidine red unheated serum test. Treponemal tests include fluorescent treponemal antibody absorption, microhemagglutination test for antibodies to T pallidum, T pallidum particle agglutination assay, T pallidum enzyme immunoassay, and chemiluminescence immunoassay. Patients who test positive for treponemal antibody will typically remain reactive for life.5,6
In the setting of discordant test results, patients with a nonreactive treponemal result are generally considered to be negative for syphilis. Discordant results with a negative nontreponemal test are more complicated, and recommendations are based on symptomatology and repeat testing.5
Treatment
When a patient has a positive nontreponemal and treponemal test, treatment is usually indicated. As with the patient in this case, treatment is always indicated for patients who have no prior history of syphilis. For patients who have a history of treated syphilis, attention must be given to titer levels on previous testing and to patient symptomatology.
The treatment for early (primary and secondary) syphilis in patients with no penicillin allergy is a single dose of penicillin G benzathine intramuscularly, at a dose of 2.4 million U. Alternative regimens include doxycycline 100 mg orally twice daily for 14 days, and azithromycin 2 g orally as a single dose; however, there is an association of treatment failure with azithromycin due to macrolide resistance.5 The patient in this case received empiric treatment targeting syphilis, gonorrhea, and chlamydia.
Conclusion
Ten years ago, the rates of primary and secondary syphilis were low, leading the infectious disease community to believe that preventive efforts had been effective. According to the CDC, however, “[current] rates…are the highest they have been in more than 20 years.”5Figure 2 demonstrates the geographic distribution of syphilis cases in the United States in 2016.7 Figure 2.
Heightened concern has prompted the CDC to promote the theme “Syphilis Strikes Back” in April 2017, which was STI Awareness Month.8 Identification of disease is critical in the ED, especially when a previously common disease has become uncommon, like the resurgence of syphilis we are now seeing.