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Clubbed Fingers and Toes

When the fingernails or toenails become rounded or flattened at the ends of the fingers and toes, it is known as clubbed fingers or toes. It is also called digital clubbing.

What causes digital clubbing in individuals with cystic fibrosis?

Poor lung function causes clubbing in people with CF. When the lungs aren’t working well, the body has trouble pushing enough oxygen through the body, so the areas farthest from the trunk, the fingers, and toes, may become deprived of oxygen. This lack of oxygen at the fingertips and toes results in changes in the nails and nail beds.

Babies and children with CF usually do not develop clubbing unless their lung function is severely limited. It tends to occur more often in teens and adult with CF during an exacerbation or as lung function declines.1,2 The liver disease and malabsorption caused by pancreatic issues common to cystic fibrosis may also contribute to clubbing.3

Symptoms of digital clubbing

Clubbing can appear quickly, often within weeks. Clubbed fingers and toes have distinct characteristics, including:

  • Nail beds are soft
  • Nails are not firmly attached and seem to float
  • Nails form a sharper angle with the cuticles
  • Tips of the finger or toe may look large, bulging, warm or red
  • Nail curves downward and looks spoon-like3

Severe clubbing usually occurs when lung function remains low for a long period of time.

Complications of clubbing on the fingers and toes

Clubbing may make it difficult for your medical team to get an accurate reading of the oxygen levels in your blood when using a fingertip pulse oximetry machine. They may have to use an ear clip instead.4

Treatment for digital clubbing

There is no treatment for clubbing of the fingers and toes, other than to try and improve lung function, and sometimes, pancreatic function. Clubbing can be reversed if lung function improves. Other health conditions that cause clubbing include some types of heart disease, lung cancer, cirrhosis of the liver, celiac disease, and Graves disease.

Written by: Jessica Johns Pool | Last reviewed: September 2019
  1. Stanford Health Care. Symptoms of Adult Cystic Fibrosis. Available at: Accessed 5/2/2019.
  2. National Organization for Rare Disorders. Cystic Fibrosis. Available at: Accessed 5/2/2019.
  3. U.S. National Library of Medicine MedlinePlus. Clubbing of the fingers or toes. Available at: Accessed 5/3/2019.
  4. Van Ginderdeuren F, et al. Influence of digital clubbing on oxygen saturation measurements by pulse-oximetry in cystic fibrosis patients. Journal of Cystic Fibrosis, Vol 5, Issue 2, 125 – 128.