What Causes Clubbed Fingers and Thumbs?

Medically Reviewed by Poonam Sachdev on April 17, 2024
7 min read

Clubbed fingers are changes to the tips of your fingers, including the nails and the skin around them. They may happen because you have another condition, like lung or heart disease, along with it. It's a congenital condition, meaning that you are born with it. 

Experts don't know the exact cause of clubbed fingers and thumbs, but it happens when certain substances in your blood are present. One of those is vascular endothelial growth factor (VEGF). You make more VEGF when your tissue can't get enough oxygen, and as a result, you grow more blood vessels, which may change the appearance of your fingers.

You don't need to treat clubbing itself, but your doctor will treat the conditions that cause it.

When you have clubbed fingers and thumbs:

  • The tissue under your nail beds swells and softens.
  • Your fingertips bulge and may be warm and red.
  • Your nails curve down and may get shiny.
  • Your nails have a more pronounced angle where they meet the skin at the base of the nail (cuticle).

Lung cancer

Lung cancer and other lung issues cause 80% of clubbing cases. If lung cancer is the cause of your clubbing, you could have symptoms such as:

  • Painful bones and joints
  • Shortness of breath
  • Persistent cough or an ongoing cough that changes
  • Cough with blood or mucus
  • Loss of appetite and weight loss
  • Fatigue
  • Chest pain
  • General weakness

Your treatment will depend on the size, location, and type of cancer you have. You may need surgery, radiation, chemotherapy, or a mix of these.

Other lung conditions

Besides lung cancer, other lung conditions can lead to clubbed fingers, such as:

Interstitial lung disease. This causes inflammation in your lungs. You may get a steroid or other medicine to slow down the disease.

Pulmonary fibrosis. Your lung tissue may get thick and stiff. You can get medicine to help you breathe.

Cystic fibrosis. This is a genetic disorder where you make too much mucus. It can build up in your airways, intestines, or other organs. Your doctor may give you medicine to clear your airways or fight infections. You may need surgery.

Some long-term infections may also be linked to clubbed fingers, such as:

Bronchiectasis. The tubes in your lungs can get damaged. You may keep getting infections when you can't get rid of mucus. You'll need to treat the cause of your bronchiectasis, like cystic fibrosis. You may also need antibiotics, good hydration, and chest physical therapy. You may need surgery.

Lung abscess. Bacteria from your mouth can get into your lungs. An infection can create a pus-filled pocket. The tissue around it will get inflamed. You'll need to take antibiotics for several weeks to get better.

If lung problems are the cause of your clubbing, you may also have:

  • Cough (with or without mucus)
  • Shortness of breath
  • A rattling sound when you breathe
  • Chest pain
  • Joints and muscles that hurt
  • Fatigue
  • Repeated chest infections
  • Fever (if you have an infection)

Heart problems

Some heart problems that may cause clubbing include:

Cyanotic congenital heart disease (CCHD). Your heart may not form the right way before you're born. Experts aren't sure why this happens. But your genes have something to do with it.

If CCHD is the cause of your clubbing, you may also have:

CCHD raises your chances of heart failure, which happens when your heart can't keep up with the needs of your body. The muscle might be weak or stiff.

Symptoms of heart failure include:

Your treatment will depend on what's wrong with your heart. You may not need to do anything. But your doctor may want you to take medicine. You may need thin tubes put into your heart. If your baby has a serious case of CCHD, they may need surgery.

Noncancerous tumor. An atrial myxoma is a benign (noncancerous) heart tumor. It may be harmless. But it can block your blood flow.

If a myxoma is the cause of your clubbing, you may also have:

Some procedures may help your heart work better, but your doctor may also want to remove the tumor through surgery.

Subacute bacterial endocarditis. You can get a serious infection of your endocardium. That's the lining of your heart. Bacteria can travel from your blood to your heart valves. The infection can get worse slowly over weeks or months. It can lower your red blood cells (anemia) and weaken your heart's blood vessels.

If subacute bacterial endocarditis is the cause of your clubbing, you may also have:

  • Mild fever
  • Slightly faster heart rate
  • More sweat
  • Weight loss
  • Joint pain
  • Small red spots in the skin or whites of your eyes
  • Red streaks under your fingernails

You'll need antibiotics that you take through an IV for 2-8 weeks. You may need surgery to fix your heart. If you have an artificial heart valve or heart defects from birth, you may have a higher chance of getting endocarditis. You may need to take antibiotics before you have any kind of dental procedure or surgery.

Other clubbed fingers causes

Less commonly, you may get clubbing if you have a thyroid issue or celiac disease. Clubbed fingers and thumbs may also happen with:

Liver cirrhosis. You can have lung and heart problems when you have an ongoing liver disease. That's because the blood vessels that transport oxygen don't work as well.

Cirrhosis may also cause:

  • Weakness
  • Poor appetite
  • Pain in the right side of your belly

You'll need to treat the cause of your liver problems to get better.

Primary hypertrophic osteoarthropathy (primary HOA). If you have this condition, your fingers may start to change around puberty and widen for about a decade.

If you have primary HOA, you may also have:

  • A lot of sweating, mostly in your hands and feet
  • Thicker skin on your face and head
  • Oily skin
  • Joint pain

You can get medicine to help with your inflammation and pain. Your doctor may give you surgery to cut your vagus nerve. Research shows it may contribute to HOA.

Inflammatory bowel disease (IBD). That includes Crohn's disease and ulcerative colitis. With IBD, your immune system creates inflammation in your small intestine or colon. IBD may cause HOA.

If IBD is the cause of your clubbing, you may also have:

Your doctor will give you medicine to lower the inflammation in your intestines. You may also need drugs that change how your immune system works, called biologics. If those don't work, you may need surgery. There is no cure for IBD.

To diagnose clubbed fingers, your doctor will:

  • Gather your medical history
  • Conduct a physical exam  
  • Take different measurements of your fingers, the skin under your nails, and the nail bed

Clubbed fingers tests

After this initial exam, your doctor will order tests tailored to the suspected cause of your clubbed fingers, which could include:

  • X-ray
  • CT scan
  • Blood tests
  • Biopsy

Finger clubbing tends to happen in five stages: 

  • Stage 1. First, the skin around your nails turns red and softens. When touched, it feels spongy.
  • Stage 2. The angle between your nail and the skin nearby increases from the normal 160°, making the nails curve as they grow. 
  • Stage 3. Over time, your fingertip expands, and the joint may become more flexible.
  • Stage 4. Eventually, your fingers look clubbed. 
  • Stage 5. Finally, your nails and the skin around them become shiny, and ridges may appear on the nails. 

This process usually takes years, but in some cases, it can happen more quickly.

With treatment, your fingers and thumbs may go back to normal. But you need to treat the health condition that's causing your clubbing. Talk to your doctor whenever you notice new clubbed fingers and thumbs.

Clubbed fingers and thumbs are often linked to underlying health issues like lung or heart disease. While the exact cause is unclear, substances in the blood, such as vascular endothelial growth factor (VEGF), which increases when tissue lacks oxygen, may cause the condition. Treatment focuses on addressing the underlying condition and may include surgery, radiation, chemotherapy, or medication.