Erythema Induratum: Case Series Illustrating the Utility of the Interferon-γ Release Assay in Determining the Association with Tuberculosis. Issue 4 (July 2013)

• Record Type: Journal Article
• Authors: Prajapati, Vimal; Steed, McKay; Grewal, Parbeer; Mahmood, Muhammad N.; Verma, Geetika; Brassard, Alain
• Is Part Of: Journal of cutaneous medicine and surgery. Volume 17:Issue 4(2013)Supplement
• Page Start: S6
• Page End: S11
• Publication Date: 2013-07
• Subjects: Dermatology -- Periodicals; Skin -- Diseases -- Treatment -- Periodicals; Skin -- Surgery -- Periodicals; Dermatology -- Canada -- Periodicals; Skin -- Diseases -- Treatment -- Canada -- Periodicals; Skin -- Surgery -- Canada -- Periodicals; 616.5005
• DOI: 10.2310/7750.2013.WOUND4
• Languages: English
• ISSNs: 1203-4754

Abstract

Background: The interferon-γ release assay (IGRA) is a novel method for detecting previous sensitization to tuberculosis (TB). Despite having several advantages over the tuberculin skin test (TST), including higher specificity and no influence from past bacille Calmette-Guérin (BCG) exposure, there are a limited number of reports describing its application in patients with erythema induratum (EI)/nodular vasculitis (NV), which is usually but not always related to TB. Objectives: The aim of our case series was to evaluate the usefulness of the IGRA for determining a TB association in patients with EI/NV. Methods: Retrospective chart reviews were conducted on four patients diagnosed with EI/NV at our institution in whom an IGRA had been performed. Results: All four subjects had positive TST results. The IGRA was also positive and therefore supported a link with TB in two cases. One patient responded completely to anti-TB therapy, whereas the second was lost to follow-up. Both cases unrelated to TB, by virtue of negative IGRAs, demonstrated complete response to immunosuppressive therapy (methotrexate), with one individual having failed anti-TB therapy first. Conclusion: Our case series highlights the utility of the IGRA for establishing a TB association in patients with EI/NV. Although limited by a small sample size, we propose adjunctive use of this test at the time of EI/NV diagnosis, especially in the setting of previous BCG exposure, so that management can be tailored according to whether an underlying relationship with TB exists.