Clubbing is enlargement of the tips of the fingers or toes and a change in the angle where the nails emerge.
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 (lung cancer, lung abscess, pulmonary fibrosis, and bronchiectasis) 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.