Swelling of the fingers in the morning may be caused by improper sleeping position, but it is not excluded that it is caused by nephritis, arthritis and other diseases. You should consult a doctor in time to find out the cause of the disease. 1. Improper sleeping position: it may be due to improper sleeping position at night, compression of the upper limbs, resulting in poor venous return of the upper limbs caused by finger swelling, this situation does not need to worry too much. 2. Nephritis: It is considered to be caused by streptococcal infection, bacterial, viral and parasitic infections. Abnormal renal function is the first symptom of nephritis, patients usually have low urine, hematuria, proteinuria, etc. Some patients may also have swollen fingers in the morning. 3. Arthritis: If the joints have been traumatized, the treatment is not complete, or there is cartilage damage in the joints, it will lead to osteoarthritis. This can be manifested as varying degrees of pain in the joints of the fingers in the morning, accompanied by swelling. Swelling of the fingers in the morning may also have other causes, such as rheumatoid arthritis and gouty arthritis, if you exclude the physiological causes, you should consult a doctor in time to clarify the specific causes, and if necessary, to carry out the appropriate treatment.