The global rise of syphilis infections and the ongoing coronavirus disease 2019 (COVID-19) pandemic are causes for concern. We herein report a rare case of concurrent primary syphilis and COVID-19.

A 29-year-old man was admitted with a diagnosis of COVID-19. Although COVID-19 pneumonia appeared during ciclesonide and favipiravir treatment, his symptoms improved without developing severe hypoxemia. A small, red ulcer on the left-side of his glans penis was noted and left inguinal lymph node swellings were detected on computed tomography (CT). He reported that his last engagement in sexual intercourse had been 3 months previously, and that his partner had subsequently been diagnosed with syphilis. Although both serum Treponema pallidum (TP) antibody and rapid plasma reagin (RPR) quantitative tests were negative on the day of admission, we clinically diagnosed a suspected case of primary syphilis and started treatment with amoxicillin (1500 mg/day). We subsequently learned that the TP antibody and RPR quantitative tests had been positive 4 days before starting syphilis treatment. Amoxicillin treatment was continued for 61 days, and the ulcer gradually improved. One year later, the RPR quantitative test was negative, and CT revealed a reduction in size of the inguinal lymph nodes and no residual signs of COVID-19 pneumonia.

The prevalence of syphilis has been increasing even during the COVID-19 pandemic, and the incidence of concurrent syphilis and COVID-19 might be higher than is recognized. Asking patients with COVID-19 about high-risk sexual behavior and genital lesions could help with early diagnosis of syphilis.

Coronavirus disease 2019

Syphilis

Treponema pallidum antibody

Rapid plasma reagin quantitative test

© 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.