Clubbed fingers occur when soft tissues at the fingertips become swollen and spongy. This straightens the natural curvature of the nail bed, causing a clubbed appearance.

A person experiencing clubbing should see a doctor to look into the underlying cause and potentially treat it as soon as possible.

Read on to learn more about what clubbed fingers are, their symptoms, common causes, diagnosis, and treatment.

Some medical conditions can cause the soft tissues at the ends of the fingers to become inflamed, which can change the shape of the finger and nail. This is called clubbing.

These changes gradually straighten the natural dip where the finger meets the nail bed and create a noticeable convex dip and hyperextension at the end finger joint.

In later stages, the nails may become especially shiny or glossy, and long vertical marks may appear on the surrounding skin. The inflammation at the fingertips tends to make them feel warm and appear enlarged and red.

Clubbing can also cause the nail beds to look and feel like they are floating on a cushion. The nail beds become loosely attached as the root of the nail plate is pushed away from the bone. The nail bed may move when someone applies pressure to it.

Clubbing tends to affect the thumb and forefinger first before progressing to the other fingers. Symptoms of clubbed fingers typically impact both hands. The condition is painless.

A range of underlying conditions can cause clubbing, usually those that interfere with oxygen exchange. That can cause low oxygen levels in the blood and tissues, known as hypoxia.

Hypoxia stimulates an increase in the density of small blood vessels called capillaries. It does this by increasing the release of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) by special cells called peripheral megakaryocytes.

The increase of PDGF and VEGF increases blood vessel vasculature and permeability, and ultimately causes tissue changes.

Several other signaling proteins are also associated with clubbed fingers, though scientists need to do more research to determine specifically how they contribute to disease development.

Clubbing is almost always a symptom of an underlying condition.

Most causes of clubbing are acquired, meaning they develop after birth.

Causes fall into one of four categories: infectious conditions, inflammatory conditions, neoplasms (abnormal growths), and vascular disease.

In some cases clubbing can also be a benign, hereditary condition that develops due to genetic mutations.

Some of the most common conditions known to cause clubbing include the following:

Lung disease

Conditions that reduce lung function can reduce circulating oxygen levels and trigger clubbing. Lung diseases, especially cancer, are the most common cause of clubbing.

Signs of lung disease include:

  • chronic cough (present 8 weeks or longer)
  • difficulty breathing, such as wheezing or shortness of breath that does not go away after exercise or occurs for no reason
  • unexplained pain in the chest that lasts a month or more, especially pain that increases when a person is breathing in and out
  • excessive mucus production that occurs for a month or more
  • coughing up blood

Cardiovascular disease

Conditions that interfere with the blood circulation can also reduce circulating oxygen levels and trigger clubbing, especially in the extremities.

Symptoms associated with cardiovascular causes of clubbing include:

  • shortness of breath
  • chronic cough or wheezing, especially if accompanied by blood-tinged mucus
  • waking up feeling tired, anxious, or restless even after a good night’s sleep
  • swelling, especially in the ankles, legs, feet, and abdomen
  • unexplained chronic exhaustion
  • memory loss or feeling disoriented
  • rapid heart palpitations
  • lack of appetite or nausea
  • discomfort in the center of the chest or in the arms, back, neck, jaw, or stomach
  • cold sweat
  • lightheadedness

Chronic liver disease

When the liver is not functioning properly, the blood vessels dilate, which can reduce the lungs’ ability to oxygenate the blood. Many people do not know they have liver disease until it has progressed to later stages.

Symptoms of late-stage liver disease include:

  • bleeding or bruising easily
  • swelling in the abdomen or legs
  • yellowish skin and eyes
  • very itchy skin
  • problems with concentration, memory, sleeping, and other mental functions
  • insulin resistance or type 2 diabetes

Chronic gastrointestinal conditions

The lungs rely on energy to function and transfer oxygen throughout the body. They get this energy from foods that the digestive system breaks down.

The intestines normally function with reduced blood oxygen levels. However, some chronic gastrointestinal (GI) conditions can cause inflammation and reduce oxygen levels further.

Symptoms associated with GI conditions known to reduce circulating oxygen levels include:

Metabolic diseases

Though far less common, autoimmune diseases, such as thyroid acropachy, can cause clubbing.

Thyroid acropachy is associated with Graves’ disease and causes irregular bone growth, swelling in the hands and feet, very dry skin, mental complications, bulging eyes, and swelling around the nose and lips.

Secondary hyperparathyroidism can also cause clubbing, as well as soft bones, muscle aching and weakness, and bone pain.

Some medications

The overuse of laxatives and the use of a group of medications called interferon alfa-2a are known to cause clubbing.

Trauma

Damage to blood vessels, or injuries or deformities that block them, can reduce circulating oxygen levels and trigger clubbing.

Symptoms of trauma typically include:

  • pain
  • bleeding
  • bruising
  • swelling
  • redness or warmth
  • loss of sensation or tingling, pins and needles, burning pain, or numbness
  • visible signs of injury, such as cuts, open sores, and broken or deformed bones

To diagnose clubbing, a doctor will perform a physical examination of the impacted fingers and take a complete patient history, asking questions about the presence or absence of symptoms of conditions associated with clubbing.

A doctor may also ask questions about someone’s family history to determine if a genetic condition may be causing the clubbing.

If clubbing is present, a doctor will normally order imaging tests to evaluate the lungs and heart, such as a chest X-ray. If these images are clear or inconclusive, a doctor may order a CT scan to look for abnormal growths.

Dozens of other tests can help determine the underlying condition and its severity, including blood tests, blood gas tests, and tests that assess lung function.

A doctor may also require biopsies and exploratory surgeries to diagnose or rule out the presence of certain GI conditions, cancer, autoimmune disorders, and blood vessel conditions.

The best treatment for clubbed fingers depends on the underlying cause.

How likely someone is to fully recover from clubbing depends almost entirely on how severe or progressed the condition is, and how early a person seeks help from a doctor to diagnose and treat it.

Treatments for conditions that may cause clubbing include:

  • cancer treatments
  • immune medications, such as biologics and immunomodulators
  • surgery to remove abnormal growths or obstructions
  • surgery to repair GI damage or remove certain structures
  • liver or lung transplant
  • oxygen therapy
  • getting enough vitamin D and calcium
  • antithyroid or thyroid hormone regulating medications
  • avoiding foods that may trigger a specific condition a person has, such as a gluten or dairy intolerance

A person may also want to maintain their overall health by eating a healthful diet. This may help lower the risk of many of the health conditions that can cause clubbed fingers.

Treating the underlying cause of clubbing can reverse this condition if the underlying condition also improves. However, when chronic, malignant, or persistent conditions cause clubbing, the condition is often long-term.

In some cases, in particular congenital cases, corrective surgery may be necessary.

Anyone who thinks they may be experiencing clubbing should contact a medical professional as soon as possible.

Getting proper treatment for the underlying cause of clubbing is usually crucial to a good outcome and reducing the risk of more serious, permanent complications.

Left untreated, several common conditions associated with clubbing can cause organ damage, disability, coma, and death.

Clubbed fingers occur when the soft tissues of the fingers swell, become spongy, and slowly straighten the curvature of the nail bed.

Clubbing typically occurs as the result of chronic gastrointestinal conditions or conditions that interfere with circulating oxygen levels. Some genetic conditions can also cause clubbing.

Cases of clubbing can resolve if treatment addresses the underlying cause. Talk to a doctor as soon as possible about potential clubbing to reduce the risk of serious, permanent complications.