A Case of Perianal Annular Rash: Atypical Presentation of Recurrent Secondary Syphilis

Abstract

Syphilis is a complex, systemic infectious disease caused by Treponema pallidum subspecies pallidum. Secondary syphilitic lesions typically manifest within 3 months following initial exposure to T. pallidum. The predominant cutaneous manifestations of secondary syphilis are macula and papule. Certain individuals with syphilis may present with an atypical rash during the secondary stage owing to immunosuppression and other factors. Herein, we report a rare case of atypical recurrent secondary syphilis around the anus in a 65-year-old woman. Based on cerebrospinal fluid findings and skin biopsy results, the patient was ultimately diagnosed as neurosyphilis and recurrent secondary syphilis. Following intravenous antibiotic therapy, the patient’s rash improved significantly. This case underscores the importance for physicians to remain vigilant regarding the possibility of syphilis when encountering cases exhibiting unusual clinical manifestations, as a definitive diagnosis necessitates a comprehensive evaluation.

Keywords:

• recurrent secondary syphilis
• perianal annular rash
• neurosyphilis
• definitive diagnosis

Ethics Approval and Informed Consent

This study was approved by the Ethics Committee of the Shanghai Skin Disease Hospital. Written informed consent for publication of her images and other clinical information were obtained from the patient. The authors confirm that our study complies with the Declaration of Helsinki.

Acknowledgments

The authors thank the patient for her cooperation in the diagnostic process.

Disclosure

The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.

Additional information

Funding

This work was supported by the National Natural Science Youth Foundation of China (grant numbers: 82103739).