Cutting off the blood circulation and supply to a finger causes the tissue to die, according to WebMD. The resulting condition is called gangrene and requires immediate medical attention.
Blood carries oxygen and nutrition to every part of the body and also provides infection-fighting antibodies. When the blood supply is constricted or cut off from any part of the body, blood is unable to circulate as required and the cells in that region begin to die, explains WebMD. Cell tissue death causes gangrene and the toes and fingers are the most susceptible to this condition. Factors that can decrease the circulation of blood, leading to the development of gangrene, include serious trauma or injury, Raynaud's phenomenon, diabetes, atherosclerosis, peripheral arterial disease and smoking.
Gangrene caused by cutting off blood circulation to the fingers, toes or any other part of the body can be classified as dry or wet gangrene. People who have diabetes or autoimmune diseases are vulnerable to dry gangrene as the reduced blood circulation is a slow and gradual process. The dying tissue remains uninfected and can turn brown, then purple and finally black. Wet gangrene is caused by a sudden and traumatic loss of blood supply to the body part. Tissue death begins rapidly and an infection sets in, notes WebMD. The infection from wet gangrene can spread quickly through the body.
Another condition that can cut off circulation to the fingers is cold hand syndrome. The condition can cause numbness or pain, swelling, hands that are very cold to the touch, tingling and discoloration. Cold hand syndrome can be caused by trauma, tumors, blood clots or vascular abnormalities, according to the University of Chicago Medicine.