Clubbed Fingers or Toes

Clubbed fingers describe fingernails or toenails that are curved downward, like a spoon. The nails may feel soft when pressed and no longer sit even with the cuticle. This often occurs along with swelling or bulging of the tips of the fingers or toes.

Clubbed fingers can be a symptom of conditions such as lung cancer, heart defects, or digestive conditions including cystic fibrosis or celiac disease. Clubbing usually happens because of long-term low levels of oxygen in the blood, known as hypoxemia.

However, clubbed nails are not always cause for alarm, especially if nail clubbing runs in your family.

This article covers the causes and symptoms of clubbed fingers, along with how clubbed fingers are diagnosed and treated.

Finger Clubbing Symptoms

Clubbing can involve your fingers and/or toes. It is typically bilateral (affecting both hands and/or feet) and it should be equal in terms of its extent on both sides.

Clubbing happens gradually and causes a change in the appearance of your fingers and/or toes. Clubbed nails become red, sponge-like, and swollen, almost like tiny balloons. From close up or a distance, clubbed nails resemble upside-down spoons.

These gradual changes may occur alone or with other symptoms, such as shortness of breath or coughing.

Features of secondary clubbing include:

• Softening of the nails
• Nail beds that soften and feel spongy
• Nails that seem to "float" instead of being firmly attached to your fingers
• Disappearing of the angle between your nails and cuticle
• Enlargement or bulging of the distal portion of your finger (where your finger meets your nail)
• Warm, red nail beds
• Nails that curve downward and look like the bottom of the round part of a spoon

Eventually, the nail and skin around the nail may become shiny, and the nail develops ridging.

If you notice signs of nail clubbing, make an appointment with your healthcare provider. Clubbed nails can be a sign of a serious condition, so it's important to have them evaluated right away. 

Causes of Clubbed Fingers

There are two types of clubbed fingers, nails, or toes with one type typically being a sign of severe disease.

Primary (idiopathic) clubbing, also called hypertrophic osteoarthropathy (HOA), is hereditary and is passed down via genes. Hereditary clubbing is simply a physical feature, like eye color and height. Several genes have been associated with primary clubbing, including the HPGD gene and the SLCO2A1 gene. Clubbing occurs alone, without an underlying health condition, and is a rare inherited trait—accounting for just 3% of all clubbing cases.

If you or your child has primary HOA, then your fingers or toes may naturally appear large, bulging, and rounded. This will be noticeable during childhood or during the teenage years, and it will not change much over time. With primary HOA, other family members are also likely to have finger clubbing and/or toe clubbing.

Secondary clubbing occurs as an effect of another health problem, such as lung cancer, heart disease, digestive conditions, or cirrhosis of the liver. In fact, secondary clubbing is caused by lung cancer or lymphoma in approximately 80% of cases.

Secondary clubbing is often related to a heart or lung condition, such as:

• Lung cancer: This cancer accounts for about 90% of all clubbing cases, with nearly 30% of lung cancer patients experiencing clubbing. The deformity is more common among people with non-small cell lung cancer than small cell lung cancer.
• Interstitial lung disease: This condition is characterized by inflammation and scarring of the tissue around the alveoli, which are tiny air sacs in the lungs.
• Human immunodeficiency virus (HIV): People with HIV have a much higher risk of developing chronic lung disease and lung infections, which can inevitably lead to clubbed fingers.
• Cystic fibrosis: This inherited disease that causes thick, sticky mucus to build up in the lungs and other organs
• Empyema: This is a collection of pus in a body cavity, most often your pleural cavity.
• Bronchiectasis: The scarred airways lead to coughing up mucus.
• Sarcoidosis: This inflammatory disease may change the structure or function of organs, such as your lungs.
  
• Other lung conditions: These include idiopathic pulmonary fibrosis and pulmonary tuberculosis
• Congenital heart disease: Heart disease that is present from birth, especially cyanotic heart disease (a defect), often leads to clubbing.
• Infectious endocarditis: This infection in the lining of the heart chambers and valves can be caused by bacteria or some other infectious organism.
• Aortic aneurysm: This is a balloon-like bulge in the aorta, the large artery that carries blood from the heart through the chest and torso.
  

Sometimes secondary nail clubbing can have causes that are unrelated to the heart or lungs, such as:

• Endocrine problems: Hyperthyroidism, especially Graves' disease, which may be accompanied by clubbing
• Celiac disease: A chronic autoimmune disease that can damage the small intestine when exposed to gluten
• Cirrhosis: A liver disease in which scar tissue replaces healthy tissue
• Crohn's disease: An inflammatory bowel disease that causes chronic inflammation of the gastrointestinal (GI) tract
• Ulcerative colitis: A chronic disease of the large intestine, in which the lining of the colon becomes inflamed and develops tiny open sores or ulcers
• Other cancers: Hodgkin's lymphoma, lung cancer, and mesothelioma (a rare cancer caused by asbestos) 
  

How Clubbing Affects Nail Beds

The medical conditions that can cause clubbing are generally associated with decreased oxygen levels. Experts suggest that clubbing occurs as your body undergoes changes in response to low oxygen.

Several processes affect the nail beds in secondary clubbing. The nail enlargement occurs due to the growth of excess soft tissue beneath the nail beds. The enlargement is associated with inflammation and a proliferation of small blood vessels in the nail beds.

Diagnosing Clubbed Fingers

Clubbing can be subtle, so it may be difficult for you and your medical team to verify this change in your fingers or toes.

There are a few objective criteria that are used to assess clubbing, and they can help in determining whether you have developed this physical change:

• Lovibond's profile sign: Normally, there is a sharp angle between the nail bed and the cuticle. When you have clubbing, the natural angle is lost as the nail angles down instead of up.
• Distal/interphalangeal depth ratio: The phalanges of your finger are the sections between each bending joint. Your distal phalange, the one that includes your nail, is normally shorter depth-wise than the neighboring phalange. Clubbing is indicated when the opposite is true.
• Schamroth's sign: The sharp angle between your nail bed and cuticle forms a tiny diamond-shaped hole when you place your hands together with the top of your nails facing each other. When this gap disappears, it is described as Schamroth's sign.

Tests

If your healthcare provider decides you have clubbing, their first move will be to ask about your family history. They'll be interested to know if it's a hereditary trait.

The provider will then do a careful history and physical exam, keeping in mind the possible causes associated with secondary clubbing. Depending on your symptoms, the tests may include:

• A chest X-ray and possibly a CT scan to look for lung cancer as well as other lung and heart-related conditions
• An electrocardiogram (EKG) and/or echocardiogram to evaluate your heart
• Arterial blood gases and/or pulmonary function tests to evaluate your lung function and look for underlying lung diseases
• Blood tests, such as liver function tests and thyroid function tests

The next move, if any, will depend on what your healthcare provider discovers.

Chronic kidney disease and other disorders such as systemic sclerosis may cause finger changes that mimic the appearance of digital clubbing. Additional tests may be needed to rule these out.

Treatment for Clubbed Fingers

Usually, the abnormal shape and size of the digits do not cause health problems, but any underlying disease that causes clubbing needs to be medically and/or surgically managed, as appropriate. Treatments may prevent your clubbing from worsening and, in rare cases, can reverse some or all of the physical features of clubbing.

There are a variety of approaches used to treat the underlying cause of clubbing. Your treatment will depend on your situation. You may need management of respiratory disease, treatment of heart disease, or interventional therapy for cancer.

Summary

Nail clubbing causes the fingers (or toes) to swell and turn red while the nails turn downward. It could be just an inherited family trait or it could be a sign of a serious medical condition involving the heart, liver, lungs, intestine, or stomach. In fact, 90% of all clubbing cases are caused by lung cancer.

Pinpointing the cause of clubbing is important. Once the cause is treated, the clubbing should go away on its own.

If you notice clubbed fingers or toes, be sure to discuss this with your healthcare provider. Clubbing can be diagnosed in your healthcare provider's office. Although clubbing itself is harmless and doesn't require treatment, it is often associated with health conditions that can worsen without treatment.