BACKGROUND: Tuberculosis is a chronic granulomatous infection caused by Mycobacterium tuberculosis, which can affect multiple organs in the human body. Lupus vulgaris is the most common clinical type of cutaneous tuberculosis in China. It typically follows a chronic course, with skin lesions that are difficult to heal, making it prone to misdiagnosis and missed diagnosis. This report presents a case of chronic lupus vulgaris that remained untreated over an exceptionally long duration, demonstrating that lupus vulgaris can manifest as a chronic inflammatory focus.

CASE REPORT: This article reports a case of a 45-year-old woman with a rash on her right earlobe for more than 30 years without pain, with occasionally itching. The rash presents as a red, thickened plaque with yellow papules and pustules on the surface. She sought treatment at hospitals and completed a few examinations. The histopathology revealed multiple epithelioid cell clusters surrounded by dense lymphocytic and histiocytic infiltration in the dermis. The interferon gamma release assay was positive. The Xpert test was positive for Mycobacterium tuberculosis. Mycobacterial culture and acid-fast staining were positive, and the cultured organism was identified as Mycobacterium tuberculosis. The chest computed tomography showed a previous lesion in the right upper lobe. Based on these findings, the diagnosis was confirmed as lupus vulgaris on the right earlobe. After anti-tuberculosis therapy, the skin lesions improved significantly.

CONCLUSIONS: The case showed that patients with persistent skin lesions, nodules, or ulcers, particularly responding poorly to treatment, should undergo appropriate examinations to rule out cutaneous tuberculosis, including lupus vulgaris.

Keywords: Lupus Vulgaris, Tuberculosis, Tuberculosis, Cutaneous, Case Reports