Ungual Tuberculosis: A Unique Clinical Case.

Cutaneous manifestations of tuberculosis (TB) are rare, particularly from an exogenous source. Involvement of the nail apparatus is extremely rare and has only previously been reported as a secondary involvement. We report the case of a 76-year-old female patient referred to our department with onychodystrophy with purulent drainage of the first left finger, which had developed during the preceding year. She had no previous traumatic history and had received treatment with multiple cycles of oral antibiotics and antimycotics, with no clinical improvement. Physical examination showed paronychia and onychodystrophy of the entire nail plate. Biopsy evaluation revealed epithelioid granulomas with central foci of necrosis, and laboratory cultures were positive for Mycobacterium tuberculosiscomplex. Chest computed tomography excluded primary pulmonary TB. X-ray of the left hand revealed the presence of dactylitis on the distal phalanx. Based on these findings, the patient was treated with rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months and with rifampicin and isoniazid for 7 months, resulting in complete resolution of the lesions. Cutaneous TB is a diagnostic challenge, particularly in rare cases such as involvement of the nail apparatus. It should be considered as a diagnostic hypothesis in cases of painless paronychia with refractory purulent drainage and associated onychodystrophy.