Clubbing of the Fingers

Clubbing is an enlargement of the ends of the fingers and a downward sloping of the nails. Although it's not caused by chronic obstructive pulmonary disease (COPD), clubbing can be a sign of coexisting lung cancer or other lung disorders in patients with COPD.

Clubbing is also known as clubbed fingers, digital clubbing, watch-glass nails, drumstick fingers, Hippocratic fingers, Hippocratic nails.

What Is Clubbing? 

Clubbing is sometimes called digital clubbing. It can affect the fingers and/or toes. It initially manifests itself as sponginess of the nail bed, along with the loss of the nail bed angle, causing the nail to curve downward and appear clubbed. Eventually, the nail and skin around the nail become shiny and the nail develops ridging. 

According to the National Institutes of Health, here are the common symptoms of clubbing:

• The nail beds soften. The nails may seem to "float" instead of being firmly attached.
• The nails form a sharper angle with the cuticle.
• The last part of the finger may appear large or bulging. It may also be warm and red.
• The nail curves downward so it looks like the round part of an upside-down spoon.

Clubbing Through History

Some scholars say that clubbing is the oldest clinical sign used in medicine. The ancient Greek physician Hippocrates--considered the father of medicine--first described this finger deformity nearly 2500 years ago in a patient.

For this reason, clubbing is sometimes referred to as a Hippocratic finger.

What Cause Clubbing?

Clubbing happens when there's extra soft tissue beneath the nail beds. Doctors don't know exactly why the soft tissue increases, but some theorize that it has to do with the levels of proteins that stimulate the growth of blood vessels.

Clubbing can be hereditary--meaning it's passed down in the genes--or it can be acquired as a symptom of disease development. Usually, the abnormal shape and size of the digits do not cause problems, but it can be a sign of disease.

Most people with clubbing have acquired bilateral clubbing, which affects both hands or both feet.

Clubbing is usually seen in individuals who have coexistent pulmonary or cardiovascular diseases, such as:

• Lung cancer (the most common cause of clubbing)
• Interstitial pulmonary fibrosis
• Lung abscess
• Pulmonary tuberculosis
• Pulmonary lymphoma
• Congestive heart failure
• Infective endocarditis
• Cyanotic congenital heart disease
• Bronchiectasis
• Cystic fibrosis 

The following are some other diseases in which clubbing may be present:

• Inflammatory bowel disease
• Liver cirrhosis
• Gastrointestinal neoplasms
• Celiac disease
• Dysentery
• Graves disease
• An overactive thyroid gland
• Other types of cancer, including liver, gastrointestinal or Hodgkin lymphoma

Clubbing and COPD

The majority of COPD patients do not have clubbing. When they do, doctors look for other causes, such as lung cancer or other lung disorders.

What To Do If You Notice Clubbing

If you notice that your fingers are clubbing, contact your doctor for an evaluation.

Clubbing can be diagnosed with simple measurements. Although clubbing itself is harmless and doesn't require treatment, oftentimes it will be associated with other symptoms that may be part of a specific health condition.

Sources:

Sarkar M., Mahesh, D.M. and Madabhavi, I. Digital clubbing. Lung India. 2012 Oct-Dec; 29(4): 354–362.

Overview of nail disorders. UpToDate. January 4, 2016.

Clubbing of the fingers or toes. MedlinePlus. April 21, 2015.

Clubbing. Merck Manual Consumer Version.

Evaluation of the Pulmonary Patient. Merck Manual Professional Version.