Yellow nail syndrome

The yellow nail syndrome (YNS) is a rare disorder principally affecting the lymphatic system.

It is characterised by a clinical triad:

1. nail discolouration (chromonychia): yellow to dark green slow-growing dystrophic nails (scleronychia) ⁹
2. lymphoedema (peripheral/primary)
3. pulmonary disease: see yellow nail syndrome (pulmonary manifestations)
   • exudative pleural effusions (least common manifestation)
   • bronchiectasis with recurrent lower respiratory tract infections. 
   • pleuritis ⁹

Other associated features include:

• rhinosinusitis

Epidemiology

It is a rare disease with an approximate incidence of less than one million/year ⁸. There may be a slightly increased female predilection ⁵. While clinical onset varies from birth to late adult life, it is thought to typically affect those in early middle age ⁵.

Associations

The syndrome can sometimes be associated with 

• malignancy ¹
• rheumatological conditions ¹
• Hashimoto thyroiditis ⁷
• Raynaud disease ⁷

Clinical presentation

Clinical features tend to be variable in severity amongst affected individuals and temporal variation is common. 

Pathology

The exact pathogenesis is not well understood although anatomical or functional lymphatic drainage abnormalities have been proposed as an underlying mechanism.

Radiographic features

Imaging is often performed in the evaluation of pulmonary manifestations.

CT

On CT chest, while individual features are non-specific, there may be evidence of

• sequelae of recurrent pulmonary infection
• pleural effusions

Treatment and prognosis

While there is no specific treatment for the syndrome, however some patients are helped with biotin and vitamin E supplementation ⁸. In addition most patients are often managed with supportive measures targeted at ameliorating the various clinical manifestations (e.g. treating respiratory infections).

The general clinical course is benign but is somewhat dependent on disease associations. In 10-30% cases there is spontaneous resolution of the condition ⁸.