Severe psoriasis with positive tuberculosis test and treatment with biologic therapy: a case report.

Psoriasis and tuberculosis (TB) are 2 conditions with high prevalence in the general population, often present simultaneously in the same patient. The crucial cytokine involved in the pathogenesis of psoriasis, tumor necrosis factor alpha (TNF-alpha), also is important in defending against mycobacteria. Therefore, it is important to screen patients for a latent TB infection (LTBI) while they are undergoing treatment with TNF-alpha antagonists. We present a case of a patient with psoriasis and LTBI who underwent treatment with etanercept.