Syphilitic Proctitis Mimicking Ulcerative Colitis

Introduction: The incidence of syphilis has increased in the past few decades in the U.S.A and it has mainly affected men who have sex with men (MSM). Syphilis may affect various organ systems like skin, genitals, and central nervous system and rarely has gastrointestinal manifestations like proctitis. Both infectious and noninfectious causes can lead to proctitis. Syphilitic proctitis is a rare clinical entity but is being reported more frequently, particularly among MSM. It generally has delayed diagnosis as it might be asymptomatic or may present with symptoms that may overlap with other disorders like inflammatory bowel disease, and nonsteroidal anti-inflammatory drug enteropathy. We report a case of syphilitic proctitis which presented with rectal pain and ulceration mimicking ulcerative colitis. Case Description/Methods: A 26-year-old man presented with on and off blood in the stools and tenesmus for a year. He identified as homosexual and denied any complaints. A digital rectal and abdominal examination was benign. His rapid plasma reagin and Treponema antibodies were positive; screening for human immunodeficiency virus and other sexually transmitted diseases was negative. A colonoscopy revealed diffuse, friable mucosal swelling, and ulceration in the rectum (Figure). Immunostaining of the rectal biopsy sample revealed many intra- and extracellular T. pallidum in the lamina propria. The patient received weekly intramuscular injections of benzylpenicillin for 3 weeks. The clinical symptoms improved and a repeat colonoscopy in 6 months after treatment, showed resolution of the proctitis. Discussion: Syphilis infections in atypical areas are often asymptomatic and relatively challenging to diagnose and should be considered in high-risk patients. Diagnosis requires a detailed history and a physical examination however, distinguishing between the other causes of proctitis will require a colonoscopy and tissue biopsy. Patients present with hematochezia, urgency, diarrhea, or constipation, and the endoscopic appearance of the rectal area may include features similar to inflammatory bowel disease.Figure 1.: Endoscopic image of redness and ulceration in the rectum.