What Is Yellow Nail Syndrome?

Yellow nail syndrome is a rare disease that affects your fingernails and toenails. People with yellow nail syndrome may also develop pulmonary and lymphatic system problems. The disease is called yellow nail syndrome because the buildup of lymph under the nails makes them appear yellow. It can occur at any age but is typically seen in people over age 50.

The lymphatic system is a part of the immune system that carries lymph, a colorless liquid with infection-fighting immune cells, throughout your body. Problems in the lymphatic system can cause lymph buildup. This results in swelling under the skin in various parts of the body. 

What Are the Causes of Yellow Nail Syndrome?

This condition is most commonly seen in people with the following: 

• Conditions that cause lymph circulation and drainage problems like lymphedema
• Certain cancers such as lung cancer, breast cancer, and lymphoma
• Autoimmune diseases such as rheumatoid arthritis
• Immunodeficiency disorders like common variable immunodeficiency and nephrotic syndrome, which affect your immune cells
• A change or mutation in the FOXC2 gene, which causes swelling in the legs known as lymphedema-distichiasis syndrome
• Possible harmful exposure to the metal titanium in dental or joint implants, medications with titanium dioxide, or the environment  

What Are Symptoms of Yellow Nail Syndrome?

The tell-tale sign of yellow nail syndrome is discolored or yellow nails and the buildup of lymph under the skin. Other yellow nail syndrome symptoms include the following:

• Fingernail and toenail dysplasia where the nails curve, separate from the nail bed, become thick, or stop growing 
• Loss of the cuticle 
• Bronchiectasis, a condition that damages the air passages or bronchi of the lungs
• Lymphatic hypoplasia (underdevelopment of lymph vessels)
• Lymphedema or swelling in your legs due to lymph buildup under the skin
• Pleural effusion or fluid buildup in the protective covering of the lungs
• Chronic sinusitis or the inflammation and infection of the sinuses
• Chronic cough
• Breathing problems
• Respiratory infections like pneumonia

Yellow nail syndrome may increase the risk of developing an infection in the tissue around the nails. 

How Is Yellow Nail Syndrome Diagnosed?

A doctor will diagnose yellow nail syndrome based on a triad or a group of three specific symptoms. They include yellow-colored nails, lung problems like chronic cough and bronchiectasis, and swelling or lymphedema in the lower limbs. 

If you have all three symptoms, your doctor will perform tests to check whether your lungs are working properly and check the swelling in your legs to confirm the diagnosis.