A 56-year-old woman presented with a 2-week history of ulcerative vulvar lesions. She had a history of unprotected sexual intercourse with her partner. Genital examinations revealed a solitary, ulcerative, and painless chancre in the left labia majora (Figure 1, A and B). A serology test for sexually transmitted infections was requested. The value of the rapid plasma regain (RPR) quantitative test was 1.3 RPR units (RU) (positive cutoff value: ≧1.0 RU), and the serum Treponema pallidium antibody titer was 15.4 sample relative light units cutoff (S/CO) (positive cutoff value, ≧1.0 S/CO). A serum fluorescent treponemal antibody absorption immunoglobulin M test was positive. A diagnosis of primary syphilis was made, and the patient received penicillin G, leading to regression of the lesion (Figure 1, C). The diagnosis of syphilis is sometimes difficult because diseases of the vulva vary and overlap in appearance. Although the syphilitic chancre may be ulcerative, it is usually painless.1 This would lead to suspicion for primary syphilis and could differentiate it from viral infections that cause vulvar ulcers, such as herpes simplex virus or varicella zoster virus.
Figure 1.
Syphilis of the vulva
A and B, A solitary, ulcerative, and painless chancre in the left labia majora. C, Regression of the lesion after treatment.
Kuratsune. Primary syphilis. Am J Obstet Gynecol Glob Rep 2023.
In the United States, the numbers of syphilis cases reported to the Centers for Disease Control and Prevention increased by 81% from 2014 to 2018.1 In Japan, syphilis has been a nationally notifiable disease under the Infectious Diseases Control Law since 1998.2 According to the Infectious Diseases Weekly Report by Japan's Ministry of Health, Labour and Welfare and the National Institute of Infectious Diseases,3 increases in the rate of women with syphilis were observed from 2010 to 2021, as shown in Figure 2. Furthermore, unfortunately, there was an estimate of more than 10,000 cases of syphilis in Japan in 2022.4 The modern epidemic of syphilis is a global concern. Physicians should recognize the importance of avoiding a delay in the diagnosis and treatment.
Figure 2.
The number of syphilis cases in Japan
The number of syphilis cases dramatically increased from 2010 to 2021. The data were extracted from the Infectious Diseases Weekly Report Surveillance Data.3
Kuratsune. Primary syphilis. Am J Obstet Gynecol Glob Rep 2023.
Footnotes
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Informed consent was given by the patient.
The authors report no conflict of interest.
References
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