Yellow Nail Syndrome

Excerpt

Yellow nail syndrome (YNS) is a rare condition defined by a presence of two of the following: (1) slow-growing, hard, yellow, and dystrophic nails, (2) lymphedema, and (3) respiratory tract disease. The earliest case of YNS was reported by Heller in 1927. However, in 1947, Samman & White published the first case series of YNS in patients with nail discoloration and lymphedema. Pulmonary disease, specifically pleural effusion, was added to the diagnostic criteria by Emerson in 1966. In general, the syndrome is acquired and affects adults over age 50. However, there are case reports of YNS occurring in children and even newborns.

Anatomically, YNS affects the fingernails, toenails, the respiratory tract, and gravity-dependent areas that can accumulate fluid (typically lower extremities). These signs and symptoms are believed to be due to dysfunction in lymphatic drainage.

Nails

As the name suggests, xanthonychia (yellow nail coloration) is a common feature of YNS; however, yellow nails are not required if two of the other clinical signs are present. Discoloration varies from pale yellow to dark green; nails can be opaque or translucent. The manifestations are commonly misdiagnosed as onychomycosis (discoloration due to fungal infection), as the nails may become thickened, hard, and curved. A quick inspection of fingernails and toenails can help expand the differential for a patient with other vague complaints without adding additional expense.

Respiratory Tract

The respiratory tract is involved in more than half of patients with YNS. The most common manifestation is a chronic cough, followed by pleural effusion. In one of the largest reviews of patients with YNS, Valdés et al. found nearly all effusions to be exudative with a lymphocytic predominance. Of the 66 subjects, approximately 70% of effusions were bilateral. Other pulmonary manifestations include bronchiectasis, recurrent pneumonia, sinusitis, and pulmonary fibrosis. Pulmonary function testing in YNS is typically unremarkable, and biopsies do not usually contribute to the diagnosis.

Lymphedema

Lymphedema typically manifests in the bilateral lower extremities and does not differ in appearance from primary lymphedema. Lymphedema occurs in 30% to 80%. Dynamic lymphatic imaging (lymphoscintigraphy) does differ between patients with edema related to YNS and those with primary lymphedema. Edema can be pitting and can be easily confused with fluid accumulation often seen in patients with decompensated congestive heart failure. This can be especially deceiving if patients present with concurrent pleural effusions. As in primary lymphedema, treatments often involve massage, compression dressing, exercises, and less commonly, surgical interventions.

Natural History

The diagnosis of YNS can be difficult because patients rarely present concurrently with all three clinical criteria. Lymphedema is the initial symptom in approximately one-third of YNS diagnoses. Prognosis and disease course depend on the individual's symptoms and timing of diagnosis. In some mild cases, the symptoms of YNS can resolve without intervention. Unfortunately, many symptoms recur despite treatment and require continuous care. YNS has the potential to affect one's quality of life, including both cosmesis and worsening functional status. Recurring soft tissue infections (e.g., cellulitis from severe lymphedema), pulmonary infections (pneumonia/empyema), and pulmonary effusions can lead to complications such as antibiotic resistance, pulmonary scarring, and protein loss.