Poncet’s Disease and Nodular Tuberculid as the Primary Presentation of Pulmonary Tuberculosis in a College Dormitory: A Case Report

Background: Tuberculosis (TB) classically presents with pulmonary symptoms, but initial manifestations can be protean. Extrapulmonary and immune-mediated presentations, such as reactive arthralgia (Poncet’s disease) and cutaneous tuberculids, pose a significant diagnostic challenge, often leading to delays in treatment and ongoing transmission. Case Presentation: A 26-year-old Ethiopian male college student presented with a 3-day history of severe, debilitating bilateral knee and ankle arthralgia and non-tender, non-erythematous nodular skin lesions on his lower extremities. Mild exertional dyspnea preceded the joint pain by one week. He lived in a crowded dormitory with three roommates, one of whom had completed treatment for pulmonary TB three months prior. Physical examination confirmed arthralgia without synovitis and tuberculid lesions. Initial workup for connective tissue disease was negative, but erythrocyte sedimentation rate (ESR) was elevated (90 mm/hr). A chest X-ray revealed hilar lymphadenopathy, and induced sputum GeneXpert Mycobacterium tuberculosis/Rifampicin Resistance assay (MTB/RIF) confirmed rifampicin-sensitive pulmonary TB. Discussion: The patient’s symptoms are consistent with immune-mediated complications of TB: Poncet’s disease (reactive arthralgia) and a nodular tuberculid. This case highlights that transmission likely occurred prior to the identification and treatment of the index case in the dormitory. The crowded living environment and period of academic stress were key epidemiological risk factors. The diagnosis underscores the necessity of considering TB in the differential for unexplained rheumatological-dermatological syndromes in endemic regions and the paramount importance of a detailed contact history. Conclusion: Tuberculosis can manifest primarily through peripheral immunologic phenomena. A high clinical suspicion for TB, driven by epidemiological clues, is essential for timely diagnosis. This case also demonstrates the critical public health imperative of systematic contact tracing in congregate settings to identify secondary cases and interrupt chains of transmission.