Abstract Introduction Yellow nail syndrome (YNS) is a rare disorder characterized by yellow nail discoloration, respiratory manifestations, and lower extremity lymphedema. Its etiology remains unclear, however associations with autoimmune diseases, malignancy, and, more recently, titanium (Ti) exposure have been reported. We present a case of YNS likely secondary to a titanium implant. Case A 53-year-old man with a history of tobacco use and left arm tendon repair using a titanium implant presented with chronic productive cough with thin yellow sputum, persistent sinus drainage, and exertional dyspnea. Symptoms began four months after surgery and progressed despite multiple courses of antibiotics, inhalers, and nasal rinses. Physical examination revealed mild bibasilar crackles, and yellow discoloration and thickening of all fingernails that were previously normal (Fig 1A). Laboratory studies were unremarkable. Nail biopsy and cultures were negative for fungal infections and did not respond to empiric antifungal therapy. Pulmonary function tests showed normal spirometry with mild air trapping and preserved diffusion capacity. Chest CT demonstrated bronchial wall thickening, mucus plugging, and tree-in-bud nodules predominant in the lower lobes (Fig 1B). Nail clippings revealed markedly elevated titanium levels (40 µg/g; reference 0). A diagnosis of YNS was made, likely secondary to titanium exposure. Patient proceeded with titanium implant removal. Discussion Although the pathogenesis of YNS is not fully understood, titanium exposure has emerged as a potential cause, with cases described after dental, orthopedic, and other metallic implants. Titanium dioxide (TiO2) is a widespread additive in foods, personal care products, and medications, yet data on its systemic toxicity in humans are limited. Mechanical stress on Ti-based implants may lead to particle release, oxidative injury, and subsequent inflammation, contributing to systemic manifestations such as YNS. This case highlights a temporal relationship between titanium implantation and the onset of YNS symptoms, with clinical improvement following implant removal. Recognition of this association is critical, as identifying and eliminating the source of Ti exposure may lead to symptom resolution. Further studies are warranted to elucidate the mechanisms underlying Ti-induced YNS and establish causality. This abstract is funded by: None
Maser et al. (Fri,) studied this question.