Case Presentation: A 56 year-old woman with well-controlled peri-rectal Crohn’s disease on infliximab presented to the hospital for management of a 2.5 year history of painful, draining vulvar dermatitis that had been biopsied twice and showed lichen simplex chronicus. Prior therapies included topical steroids and multiple antibiotic courses without significant or sustained improvement. MRI to rule out fistulization due to Crohn’s showed several abscesses and no fistulous tracts, so she was admitted to the Hospitalist service for further workup. Examination of the vulva revealed deep dermal inflammation with a draining sinus tract of the right labia majora and dyspigmentation. Dermatology and Gynecology suspected either uncontrolled bacterial infection, cutaneous Crohn’s disease, or hidradenitis suppurativa with overlying infection. Gastroenterology felt that cutaneous Crohn’s was unlikely as she had well-controlled disease. Abscesses were aspirated but cultures were negative.  Because of the diagnostic uncertainty, a third biopsy was planned. Gynecology-oncology and plastic surgery were available for large biopsy in the operating room or vulvectomy with flap if repeat bedside biopsy was inconclusive. However, bedside wedge biopsy showed focal non-caseating granulomas and patchy plasmacytic infiltrate, consistent with cutaneous Crohn’s disease.  She was started on metronidazole as it has demonstrated improvement in cutaneous Crohn’s disease.  Two weeks after discharge, the erythema, pruritus, and drainage had significantly improved although the swelling of the right labia majora remained. The primary treatment of cutaneous Crohn’s disease is alternate immunosuppressive agent so it was recommended that her infliximab be changed.

Discussion: Crohn’s disease should be considered with any abscess or draining sinus in the lower pelvis as it can be the presenting symptom of the disease and sometimes represents fistulization from the colon, even if there are no gastrointestinal symptoms to suggest uncontrolled disease. Skin symptoms may not mirror disease activity and thus can be easily misdiagnosed.  The key to diagnosis in this case was a high index of suspicion that this could be cutaneous Crohn’s, which led to a third biopsy and ultimately, directed treatment. A multi-disciplinary team led by the hospitalist was needed for optimal care as Crohn’s disease can have many extra-luminal manifestations. Metronidazole improved symptoms, and further improvement with switch to an alternative immunomodulatory agent is expected.  However, a two-year delay in diagnosis led to substantial morbidity with pain, multiple weeks of antibiotic exposure, disfigurement from scarring, and decreased quality of life. 

Conclusions: There should be a high index of suspicion for cutaneous Crohn’s disease in a Crohn’s patient with unusual skin lesions, especially in the lower pelvis or perineum.  Metronidazole can control symptoms locally, but the mainstay of treatment is the addition of or change in immunomodulatory therapy.  Cutaneous Crohn’s disease is often misdiagnosed and requires a multidisciplinary approach for both diagnosis and treatment.