Yellow Nail Syndrome Presenting With a Complete Clinical Triad: A Report of a Rare Case.

Yellow nail syndrome (YNS) is a rare disorder characterised by a triad of yellow nail discoloration, lymphoedema, and respiratory manifestations, including recurrent pleural effusions. A few hundred cases have been reported worldwide. Diagnosis is primarily clinical, as no definitive biomarkers exist, and the complete triad is seen in only a minority of patients. We report a 76-year-old male who presented with recurrent pleural effusions, non-pitting lower-limb oedema, and characteristic nail changes. Timely recognition of the classical triad allowed appropriate intervention, including indwelling pleural catheter placement and talc pleurodesis, leading to symptomatic improvement. This case highlights the importance of clinical vigilance in evaluating unexplained pleural effusions in older adults.