Pleural effusion in psoriatic arthritis patients: a case series and review of the literature.

Psoriatic arthritis (PsA) is a chronic inflammatory disease associated with psoriasis. Pulmonary involvement is a rare extra-articular manifestation of the disease characterized by rigidity of the chest wall and apical pulmonary fibrosis. Pleural effusion is uncommon in PsA. We present four cases of patients with PsA who developed pleural effusions. We report for the first time a PsA patient who was drug-naïve and developed unilateral pleuritis. We also describe one PsA case with pleuritis while he was on methotrexate (MTX) and two PsA cases on tumor necrosis factor (TNF) inhibitors. The literature review revealed six cases with pleural effusion, which were drug-induced. These patients presented pleural effusions while they were treated with MTX (2 patients) and TNF inhibitors (4 patients). In PsA patients with pleuritis, a detailed investigation to rule out infections is necessary. In addition, increased pharmacovigilance will detect cases of drug-induced serositis.