When Crohn's Disease Is Confined to the Mouth: A Diagnostic Challenge-A Case Report and Review of the Literature.

This article explores a rare and diagnostically challenging form of Crohn's disease, known as Oral Crohn's Disease (OCD), in which the condition is confined to the oral cavity without gastrointestinal involvement. Additionally, Crohn's disease is typically associated with digestive manifestations, and oral lesions may occasionally represent the first- or even the sole- signs of the disease, making diagnosis difficult due to their non-specific presentation. We report the case of a 22-year-old presenting woman suffering from chronic painful gingivitis and macrocheilitis, in the absence of gastrointestinal symptoms. Despite multiple topical treatments and an initial non-specific histopathological report, a multidisciplinary case discussion and re-evaluation of biopsies led to the diagnosis of OCD. Comprehensive gastrointestinal assessments revealed no intestinal involvement. Owing to the persistence of symptoms and resistance to topical therapies, the patient was subsequently treated with an anti-TNFα (Tumor Necrosis Factor alpha) biologic agent. To contextualize this case, we conducted a literature review and identified six similar cases published between 2000 and 2025. Reported patients presenting with symptoms such as lip swelling, cheilitis, mucosal ulcerations, and gingivitis. Histopathological findings consistently demonstrate non-caseating granulomas and inflammatory cell infiltration. Most cases responded favorably to corticosteroids, while some required systemic or biologic therapy. The article highlights that OCD remains underrecognized due to its variable clinical presentation and absence of gastrointestinal manifestations. It emphasizes the importance of integrating clinical, histological, and exclusion-based diagnostic criteria and advocates for a multidisciplinary approach involving dental surgeons, dermatologists, pathologists, and gastroenterologists. Early recognition and long-term monitoring are essential, as gastrointestinal involvement may develop years after the onset of oral symptoms.