Clubbing occurs when the amount of soft tissue beneath the nail beds increases. It is not clear why the soft tissue increases, but it may be related to the levels of proteins that stimulate blood vessel growth. Clubbing occurs in some lung disorders (such as lung cancer Lung Cancer Lung cancer is the leading cause of cancer death in both men and women. About 85% of cases are related to cigarette smoking. One common symptom is a persistent cough or a change in the character... read more , lung abscess Abscess in the Lungs A lung abscess is a pus-filled cavity in the lung surrounded by inflamed tissue and caused by an infection. A lung abscess is usually caused by bacteria that normally live in the mouth and are... read more , pulmonary fibrosis Idiopathic Pulmonary Fibrosis Idiopathic pulmonary fibrosis is the most common form of idiopathic interstitial pneumonia. Idiopathic pulmonary fibrosis affects mostly people over the age of 50, usually former smokers. People... read more , and bronchiectasis Bronchiectasis Bronchiectasis is an irreversible widening (dilation) of portions of the breathing tubes or airways (bronchi) resulting from damage to the airway wall. The most common cause is severe or repeated... read more ) but not in others (pneumonia and asthma). Clubbing also occurs in some congenital heart disorders and liver disorders. In some cases, clubbing may be inherited and not indicate any disorder. Clubbing itself does not need treatment.