Also known as hyperglycemia, diabetes causes sugar to spill into the urine, causing excessive thirst, increased urination, weight loss, blurry vision, and itching. This condition leads to long-term complications including poor circulation resulting in tingling, cold or blue toes and painful calves while walking. another complication involves nerve damage leading to decreased sensation, or may involve severe painthat is often worse at night. This nerve damage may also result in the development of hammertoes, bunions, foot ulcers, and other deformities. Because an injury can occur without pain, and thereby go unnoticed, it is necessary that patients carefully inspect their feet daily and to consult theri physician for any potential problemsome lesions.