Finger clubbing means specific changes in the shape of your fingers and fingernails. It is also called digital clubbing or Hippocratic fingers. People with heart or lung problems sometimes have these changes.
Who gets it
Finger clubbing happens in more than 3 out of 10 people (35%) with non small cell lung cancer but only about 4 out of 100 people (4%) with small cell lung cancer. You may also get it with mesothelioma.
What it is
Finger clubbing happens in stages:
- the base of the nail (nail bed) becomes soft and the skin next to the nail bed becomes shiny
- the nails then curve more than normal when looked at from the side (this is called Scarmouth's sign)
- the ends of the fingers may then get larger (when they are called drumstick fingers)
Hypertrophic pulmonary osteoarthropathy (HPOA)
In the later stages of finger clubbing, extra areas of bone might form on the finger joints, wrists and ankles. This is sometimes mistaken for arthritis and is called hypertrophic pulmonary osteoarthropathy (HPOA).
What causes it
Clubbing is thought to be caused by fluid collecting in the soft tissues at the ends of the fingers. This is caused by more blood flowing to the area than usual. But we don’t fully understand why this happens.
It may be due to the tumour producing particular chemicals or hormones (this is called a paraneoplastic syndrome).