Hidden tuberculous lymphadenitis and miliary tuberculosis in an erythema induratum patient: Usefulness of interferon-γ release assays in the diagnosis

摘要

Erythema induratum (El) may be associated with tuberculosis (TB) infection. However, the results of Mycobacterium tuberculosis (MTB) cultures are rarely positive, and the tuberculin skin test (TST) is of limited utility in populations exposed to the bacillus Calmette-Guerin (BCG). Interferon-gamma release assays (IGRA) are alternative options to the TST and have high specificity. We herein report a case of TB lymphadenitis and miliary TB in patient with history of El, which was diagnosed with the aid of an IGRA.An 18-year-old female presented with several days' history of multiple tender erythematous subcutaneous nodules on both lower legs and forearms (Fig. 1a). She had no systemic symptoms and palpable lymph nodes. A chest X-ray was normal.