BH29 Nailing the diagnosis

Abstract Yellow nail syndrome is a rare disorder characterized by a triad of yellow nail discoloration, lymphoedema and respiratory manifestations. There are fewer than 400 published case reports and the estimated prevalence is less than 1 in 1 million (Vignes S, Baran R. Yellow nail syndrome: a review. Orphanet J Rare Dis 2017; 12: 42). A White man in his 60s was referred to the dermatology clinic in a regional hospital in Ireland with a 10-year history of nail dystrophy. He had smoked a long time ago and his background was notable for a chronic cough, present for approximately 15 years, as well as chronic rhinosinusitis. He reported a progressive history of thickened and discoloured nails, affecting the fingernails and hallux nails bilaterally. Prior to dermatology review he had multiple courses of over-the-counter topical treatments, as well as topical antifungal agents from his general practitioner. On examination in early 2024 there was evidence of increased side-to-side curvature of the nails and a loss of lunulae. A differential diagnosis of yellow nail syndrome was raised and he was booked for 6-monthly follow-up. Other differential diagnoses included onychomycosis and nail psoriasis. Routine bloods were within normal ranges, and fungal nail clippings were negative. The patient had attended the respiratory clinic for his chronic cough since 2022 and computed tomography of the thorax was carried out in 2024, which demonstrated bilateral lower-lobe bronchiectasis. He subsequently was followed up in the dermatology outpatients department, and with the presence of two features out of the triad of thickened yellow nails, primary lymphoedema and respiratory tract involvement, a diagnosis of yellow nail syndrome was confirmed. He remains under review in the respiratory and dermatology services.