Nail abnormalities are often pointers to various systemic illnesses as well as local conditions. These manifest as changes in the color, shape and growth pattern of the nails. One of these is the yellow nail syndrome.
Yellow nails are caused by various conditions, such as:
The presence of icterus causes yellowish discoloration of the nails when the bilirubin deposition is heavy. In such cases, the patient may have high bilirubin levels due to severe hepatic disease, or because of the breakdown of blood cell hemoglobin due to hemolysis.
Individuals who smoke heavily may show a characteristic yellowish discoloration of the nails due to the deposition of nicotine.
Nails may turn yellow in diseases such as:
Yellow nails coexist with lymphedema and pleural effusion in this rare genetic condition. First described in 1964, it affects both men and women with equal incidence. It may have a familial basis or occur sporadically.
It is thought to have an autosomal dominant inheritance. The lymphedema may be either congenital or acquired. The cause may be structural or functional.
The age at which it starts may be between 40 and 60 years. All features may not start at the same time.
In the yellow nails syndrome, the nails appear yellowish and thickened in 85% of cases. In some patients, it seems as if the nails have stopped growing. Though they remain smooth in most cases, in a small minority they develop ridges or become excessively curved. The cuticle may be lost. Some or all nails may show the characteristic features. The nail may also become detached from the nail bed, a process called onycholysis.
Lymphatic swelling is seen in 8 of every 10 patients, usually in the lower extremities. In most patients, the nail changes have already occurred by this time. The swelling is of the non-pitting type. The fluid is usually serous (in three-fourths of patients). Chylous fluid is seen in just over a fifth, while purulent effusion is rare, being found in less than 4%. In the vast majority, the fluid is exudative in origin.
Pleural effusion may occur repeatedly, and may be severe. Seen on both sides in about 68% of patients, it may be due to chylothorax, or infections of the lung. In a few patients, it is of unknown etiology. In about 85% there is also a chronic cough due to bronchiectasis.
Other associated lung conditions include bronchiectasis, chronic sinusitis, pneumonia, or hyper-reactive airways.
The diagnosis of yellow nails syndrome is a clinical one. Despite the name, the nail changes are not pathognomonic of the condition. Thus it may be diagnosed if otherwise unexplained pleural effusion and lymphedema are present, even without nail discoloration.
The nail changes may revert spontaneously in approximately 1 of 2 patients. In some cases, topical vitamin E in dimethyl sulfoxide helped to resolve the discoloration. Other treatments include oral vitamin E, itraconazole, and oral zinc therapy.
Oral zinc tablets also helped to reduce the swelling due to lymphatic obstruction. Other standard therapies are also useful, including limb elevation and compressive bandages.
Pleural effusion may be helped by adopting a low-fat diet, with supplementary medium-chain fatty acids. This is because the portal lymphatics, rather than the intestinal lymphatics, absorb medium-chain fatty acids. Diuretics are also used. Octreotide is administered to reduce pleural effusion due to chyle leakage.
Surgical options for pleural effusion include pleurectomy, pleurodesis, or shunting the fluid via a pleuroperitoneal or pleurovenous shunt.
Pleural effusions may be so large as to cause respiratory failure. In other cases, shunt complications may occur, including intestinal distension with a pleuroperitoneal shunt. Loss of fatty acids secondary to chyle drainage may result in deficiency of adequate nutrition.
The occurrence of repeated large pleural effusion is the most worrisome symptom, but may be managed in most cases as above. The nail changes often resolve, while respiratory failure is rare.