Congenital Syphilis Cases Are Rapidly Rising: How to Manage Them

Column Author: Chris Day, MD | Pediatric Infectious Diseases; Director, Transplant Infectious Disease Services; Medical Director, Travel Medicine; Assistant Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Assistant Professor of Pediatrics, University of Kansas School of Medicine

Column Editor: Angela Myers, MD, MPH | Pediatric Infectious Diseases; Division Director, Infectious Diseases; Medical Director, Center for Wellbeing; Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Assistant Professor of Pediatrics, University of Kansas School of Medicine

Syphilis rates reached an all-time low in the year 2000 with 5,979 total cases of primary and secondary syphilis reported. Jeffrey Koplan, then director of the Centers for Disease Control and Prevention (CDC), noted that progress was being made in eliminating the infection.¹ Since that time the trend in the annual number of reported cases has reversed, at first slowly, and then in the past decade much more rapidly. In 2020 there were 133,954 total case of syphilis and in 2021, the most recent year for which the CDC provides data, there were 176,713 cases. Men who have sex with men (MSM) have long been the most affected group, but cases in women have more than tripled since 2017 (from 3,722 to 11,772). Consequently, cases of congenital syphilis have also been rising dramatically in the past decade: 334 cases were reported in 2012, but 2,157 cases in 2020 and 2,855 cases in 2021.^2,3 The increases in case numbers from 2020 to 2021 appear to be related to the COVID-19 pandemic, likely due to a number of associated factors including reduced screening because of altered health department priorities during the pandemic, reduced access to in-person medical care, and changes in sexual behavior.⁴ Causes for the longer-term increases in cases are likely similarly complex and do not appear to be fully understood.  

As cases of congenital syphilis have become much more common, proficiency with managing them has become increasingly important. It helps to understand the basics of diagnosis and treatment in both the potentially exposed newborn and the child’s mother. Per the American Academy of Pediatrics (AAP) Red Book, “No newborn infant should be discharged from the hospital without determination of the mother’s serologic status for syphilis.”

Decisions on treatment of infants potentially exposed to maternal syphilis infection must begin with understanding the mother’s diagnosis and treatment history. Understanding how the maternal diagnosis was made has been complicated in recent years by the introduction of a reverse-sequence approach to syphilis testing in many centers (including Children’s Mercy Kansas City) as a cost-saving measure. In reverse-sequence testing, instead of a rapid plasma reagin (RPR) or venereal disease research laboratory (VDRL) (both “non-treponemal tests”) being the initial test, a specific treponemal test (typically labeled as a syphilis antibody, at least locally) is used instead as a screen. After a positive initial test, a non-treponemal test is used next to confirm the diagnosis. Additional confusion can occur when the RPR or VDRL is negative as further additional testing is now needed to be able to reject or confirm a diagnosis of syphilis. Another treponemal test, this time the treponema pallidum particle agglutination (TP-PA), is obtained. If this is also negative, the nontreponemal tests may need to be repeated in two to four weeks.

It is crucial to know whether maternal treatment was adequate for the stage of illness: a distinction must be made between 1) primary, secondary and early latent syphilis (for any of which, treatment for a pregnant women should typically be a single dose of IM penicillin G benzathine), and 2) late latent syphilis, tertiary syphilis and neurosyphilis (for which longer courses of penicillin are necessary). Primary syphilis is the stage at which the initial chancre is present. Secondary syphilis can occur one to two months later with a variety of symptoms that may include fever, sore throat and mucocutaneous lesions. Early latent syphilis is syphilis that has been provably present for less than a year. When latent syphilis is identified by screening without prior testing in the past year, it should be treated as late latent syphilis (three weekly doses a week apart of IM penicillin G benzathine). Per the AAP Red Book, a delay in any dose of therapy beyond nine days between doses will require repeating the full course of therapy.

Potentially exposed infants should have a nontreponemal test performed in the immediate newborn period. Most infants for whom a nontreponemal test is indicated will need some form of penicillin treatment, and many will need some additional evaluation including cerebrospinal fluid (CSF) analysis, a complete blood count (CBC), and possibly long-bone films, even if the initial infant nontreponemal test is negative. Follow-up, including repeat nontreponemal testing every two to three months and careful exams at every well-child visit, will be required. The AAP Red Book chapter on syphilis, in particular Figure 3.15 and Table 3.66, is invaluable in making decisions for the care of infants with congenital syphilis. In pediatric infectious diseases, we are eager to assist with management of any infant with congenital syphilis, but we do appreciate having specific data points (as outlined in the box below, reflecting information needed to proceed through the algorithm in Fig. 3.15 in the AAP Red Book

To review prior to calling your ID consultant:

1. Documentation of the maternal syphilis diagnosis (both treponemal and nontreponemal testing as well as any symptoms and timing of those symptoms if known) with date (if reverse-sequence testing, will need TP-PA result if RPR negative).
2. Documentation of maternal RPRs (dates, titers (1:2, 1:32, etc.)).
3. Documentation of maternal treatment (including all dates of treatment, treatment given).
4. Infant RPR if available

It will make your call more efficient if you have reviewed Fig. 3.15 and Table 3.66 (AAP Red Book) as they apply to your patient. Your ID consultant will also be using these resources when you call!

References:

1. S. syphilis rate declines to all-time low in 2000. Centers for Disease Control and Prevention. November 28, 2001. https://www.cdc.gov/stopsyphilis/media/SyphRate11-28-01.htm
2. Sexually transmitted disease surveillance 2021. Centers for Disease Control and Prevention. April 11, 2023. https://www.cdc.gov/std/statistics/2021/default.htm
3. Trends in reported cases and rates of reported cases for nationally notifiable STDs, United States, 2017-2021. Centers for Disease Control and Prevention. July 7, 2022. https://www.cdc.gov/std/statistics/2021/Table-24_Prelim-2021-Data-8-29-22.pdf
4. Impact of COVID-19 on STDs. Centers for Disease Control and Prevention. April 11, 2023. https://www.cdc.gov/std/statistics/2021/impact.htm
5. Committee on Infectious Diseases, American Academy of Pediatrics. Syphilis. In Kimberlin DW, Barnett ED, Lynfield R, Sawyer MH, eds. Red Book: 2021-2024 Report of the Committee on Infectious Diseases. 32nd ed. American Academy of Pediatrics; 2021:729-744.