Capsaicin-Triggered Vaginal Burning Due to Obstructed Rectovaginal Fistula: A Rare Case of Perineal Coproliths

BACKGROUND Rectovaginal fistulas (RVFs) typically present with vaginal flatus or fecal leakage, facilitating early diagnosis. However, atypical or occult presentations can obscure recognition. We report an unusual RVF manifesting as vaginal burning triggered by spicy food, resulting from capsaicin transfer through a fistulous tract obstructed by perineal coproliths - a rare mechanism that concealed classic symptoms. CASE REPORT A 52-year-old multiparous woman with prior pelvic surgeries experienced 2 years of vaginal burning exclusively after consuming spicy food, which was initially misdiagnosed as vaginitis. Symptoms worsened following a diarrheal episode. Physical examination revealed a 2-cm firm perineal mass. Pelvic MRI identified a low intersphincteric fistula (Parks classification), and ultrasound revealed calcification. Urinalysis showed microscopic hematuria (36.7 RBC/μL); other investigations were unremarkable. Surgical exploration exposed a 2-cm cavity between the rectum and vagina, obstructed by coproliths. After coprolith removal and seton placement, the patient's symptoms resolved. The postoperative course was uneventful, with complete symptom resolution by 2 weeks. Notably, the patient's recovery was achieved without stoma diversion, suggesting that a conservative staged approach may suffice for selected low-level, well-drained fistulas. A 1-year telephone follow-up with the patient confirmed sustained recovery, with normal bowel and urinary function. CONCLUSIONS This case highlights an exceptionally rare presentation of RVF with diet-triggered symptoms. Migration of capsaicin through an occult fistulous tract can cause isolated vaginal burning, while coprolith obstruction can mask classical signs and delay diagnosis. Recognition of such atypical, food-induced symptom patterns may guide earlier identification and individualized surgical management in patients with prior pelvic surgery.