Erythema induratum: case series illustrating the utility of the interferon-γ release assay in determining the association with tuberculosis.

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.

• Authors: Vimal Prajapati, McKay Steed, Parbeer Grewal, Muhammad N Mahmood, Geetika Verma, Alain Brassard
• Journal: Journal of cutaneous medicine and surgery (J Cutan Med Surg) Vol. 17 Suppl 1 Pg. S6-S11 (Oct 2013) ISSN: 1203-4754 [Print] United States
• PMID: 24144256 (Publication Type: Case Reports, Journal Article)

Chemical References

• Interferon-gamma

Topics

• Adult
• Diagnosis, Differential
• Enzyme-Linked Immunosorbent Assay
• Erythema Induratum (diagnosis, metabolism)
• Female
• Humans
• Interferon-gamma (metabolism)
• Interferon-gamma Release Tests (methods)
• Retrospective Studies
• Tuberculin Test
• Tuberculosis (diagnosis)