Swollen fingers in diabetic patients are not usually fatal. Diabetic finger swelling can be seen in cases of diabetes itself causes, mosquito bites, localized infections, etc. Diabetes mellitus is a non-fatal disease, but can induce other fatal complications such as ketoacidosis, hyperosmolar hyperglycemia syndrome, coronary heart disease, hemorrhagic stroke and other fatal diseases, so it is recommended to strictly control blood sugar. 1. Complications of diabetes mellitus itself: swelling of the limbs is a common clinical symptom of moderate to advanced diabetic nephropathy, patients may have hypoproteinemia, swelling of the limbs, more obvious in the lower limbs, fingers may also have swelling. 2. Mosquito bites: mosquito bites can cause skin swelling and pain, which is an inflammatory reaction caused by mosquito toxin stimulation. 3. Localized infections: localized infections after finger trauma, especially in diabetic patients, can lead to finger swelling after infection, and need to be treated with antibiotics. Seek medical attention if you feel unwell.