Background: With increasing use of immunosuppressive therapy, including tumor necrosis factor a inhibitors, there is concern about infectious complications, including reactivation of latent Mycobacterium tuberculosis infection. Routine testing prior to administration of systemic immunosuppression includes the tuberculin skin test, which lacks sensitivity and specificity and may be difficult to interpret in the presence of extensive cutaneous disease. Treatment of individuals with latent tuberculosis infection is recommended when immunosuppressive medications are to be employed. Observations: We report a case in which a diagnosis of latent tuberculosis infection in a patient with extensive bullous pemphigoid was clarified by the use of an interferon-γ release assay after equivocal tuberculin skin test results. Conclusion: Interferon-γ release assays are useful adjuncts to the tuberculin skin test in the diagnosis of latent tuberculosis infection in the setting of extensive cutaneous disease.
ALTERNATIVES TO THE TUBERCULIN SKIN TEST: INTERFERON-γ ASSAYS IN THE DIAGNOSIS OF MYCOBACTERIUM TUBERCULOSIS INFECTION
