Yellow Nail Syndrome is a rare medical disorder that primarily affects the nails, respiratory system, and lymphatic circulation, leading to symptoms involving the lungs and lower limbs. It is an uncommon condition that requires clinical evaluation to differentiate it from other nail or systemic disorders.

Diagnosis of Yellow Nail Syndrome is mainly clinical, meaning doctors identify it based on characteristic signs and symptoms rather than a single definitive lab test.

• Clinical evaluation: Diagnosis usually begins with recognizing the typical clinical features. Doctors look for yellow, thickened nails along with lymphedema (swelling) and respiratory symptoms such as chronic cough or fluid around the lungs. In many cases, having at least two of these features together supports the diagnosis. ​
• Medical history: A detailed health history is important to understand the timeline and progression of symptoms. The doctor will ask about changes in nail appearance, swelling of the legs or arms, and any ongoing respiratory problems or infections. ​
• Physical examination: The physical examination focuses on inspection of the nails and limbs, checking for swelling and abnormal nail appearance, and examining the chest for signs of respiratory involvement. These findings help confirm whether the typical pattern of YNS is present.
• Laboratory tests: Blood tests can be done to rule out other conditions that may cause similar symptoms, such as autoimmune diseases or infections, even though there is no specific blood test for yellow nail syndrome itself.
• Imaging studies: Imaging such as chest X-rays or CT scans may be performed to assess lung health and detect complications like pleural effusion or other respiratory conditions that can accompany this syndrome.
• Specialized procedures: In selected cases, examination of a nail clipping or biopsy of the nail or nearby tissue may be used to exclude other nail disorders, such as fungal infection or psoriasis, when the clinical picture is unclear

Yellow Nail Syndrome is rare, and its exact cause is unknown, but certain factors are associated with a higher likelihood of developing the condition.

• Older age: YNS most often develops in adults over age 50, suggesting that age-related changes in the lymphatic and respiratory systems may increase risk.​
• Lymphatic problems: Dysfunction of the lymphatic system, which helps drain fluid from tissues, is thought to be central to YNS and may predispose people to swelling and nail changes. ​
• Autoimmune and chronic conditions: People with autoimmune diseases (such as rheumatoid arthritis), thyroid disorders, or nephrotic syndrome have a higher chance of developing YNS, likely because these illnesses affect immune and systemic function.
• Cancer and immunodeficiency: Certain cancers and immune system disorders are linked with YNS, possibly because they disrupt lymphatic function and fluid balance.
• Lymphatic dysfunction: Problems with the lymphatic system, which helps drain fluid from tissues, appear central to many cases, as impaired lymph flow can contribute to both swelling and nail changes.
• Possible genetic factors: Some reports suggest a genetic predisposition, as YNS has occurred in families and may involve inherited traits related to lymphatic or immune function.​
• Titanium exposure (rare): In uncommon situations, titanium exposure from implants or products has been observed in people with YNS, and removing titanium sources has occasionally led to improvement.​

Yellow nail syndrome treatments may include:

Vitamin E: ​Oral or topical vitamin E supplements are often used to help improve nail discoloration and slow the progression of nail changes, though results vary between patients.

Corticosteroids:​ Topical or sometimes systemic corticosteroids may be given to reduce inflammation and support improvement in nail and skin symptoms.

Antibiotics: ​Antibiotics are used to treat recurrent respiratory infections such as sinusitis or bronchiectasis, which frequently occur in YNS and can worsen symptoms.

Diuretics and diet: For fluid buildup, diuretics and a low-fat diet with medium-chain triglycerides may help reduce lymphatic load and manage swelling or chylous effusions. ​

Drainage procedures: When pleural effusions (fluid around the lungs) are significant, procedures like thoracentesis, pleurodesis, or surgical drainage may be required to relieve symptoms and prevent complications.

Lymphedema therapies: ​Management of swelling typically includes manual lymphatic drainage, compression garments, massage, exercise, and skin care to improve lymph flow and reduce tissue fluid.

Bronchodilators and supportive lung care: For chronic cough or breathlessness, bronchodilators, chest physiotherapy, and pulmonary support may be helpful alongside treating infections. ​

Somatostatin analogues: In some cases with chylous effusion, medications like octreotide (a somatostatin analogue) can improve lymphatic flow and fluid management.

Other medications: Other reported options in individual cases include zinc supplements, antifungal agents (when infection is suspected), macrolide antibiotics like clarithromycin, or novel approaches such as oral terbinafine and topical minoxidil for resistant nail symptoms. ​

Underlying condition treatment: If YNS occurs with an associated disease, such as autoimmune disorders or cancer, treating that condition can improve overall outcomes. ​