The causes of swollen fingertips can be summarized as follows. First, the heat of summer. Heat causes blood vessels to dilate, allowing more heat to be lost from the skin to keep the body temperature from rising. The dilation of blood vessels can cause increased blood flow to the tissues, which can cause swelling. Second, consume too much salt. Dishes in restaurants, bought snacks and fried foods contain a lot of salt, causing water and sodium retention in the body causing swelling. Third, sleeping posture. Because the posture is not right when sleeping, the blood vessels in the arm are compressed, resulting in the feeling of hand swelling. Fourth, eating more at night. Eat more or drink more water at night, so that the cells are too full, and after waking up in the morning, the fingers feel swollen and can not be made into a fist. Fifth, malnutrition edema. Sixth, lymphedema. Seventh, carpal tunnel syndrome, also known as mouse hand or delayed median nerve palsy, is the median nerve in the carpal tunnel pressure caused by the pain and numbness of the index finger, middle finger and thumb muscle weakness and other symptoms. As the nerve that moves from the forearm to the palm of the hand is compressed in the wrist area, it triggers swelling and weakness in the hand, which may also be accompanied by pain, burning, tingling and numbness. Eighth, Raynaud’s disease. Raynaud’s disease, which refers to paroxysmal spasms of the arteries in the extremities caused by constriction of the vascular arteries, is usually triggered by cold weather or stress. The low blood flow due to the constriction of the arteries results in cold, numb fingers, and when the temperature warms up or the pressure disappears, the blood circulation returns to normal, and that’s when the swelling occurs. Ninth, osteoarthritis, rheumatic or rheumatoid arthritis can cause swelling and pain in the joints.