The Challenging Evaluation of Patients with Severe Psoriasis for Latent Tuberculosis: An Important Indication for IGRA.

It is well-established that tumour necrosis factor (TNF)-α-antagonist regimens are advisable for the control of moderate to severe psoriasis; however the application of these agents is associated with increased risk of TB reactivation. Screening for latent tuberculosis infection (LTBI) is indispensable prior to treatment inception in order to diminish the risk of active TB. Although tuberculin skin test (TST) still represents a useful tool for LTBI detection, it is difficult to be performed and read in patients with extensive psoriatic lesions. In this paper, we report the case of a 65-year-old male with severe psoriasis, who was evaluated by an interferon-gamma release assay (IGRA) for LTBI diagnosis prior to anti-TNF-α therapy. Furthermore, the physiological aspects of interferon-gamma release assays are discussed emphasizing the value of these novel immunodiagnostic tests (IGRAs) for presumable LTBI in all patients with extensive skin disorders.