The slow healing of wounds sets the stage for some of the grimmest diabetes complications. Minor wounds can advance to cellulitis, which is a serious infection. Cellulitis can advance to tissue necrosis, or tissue death. Tissue necrosis can then extend from the soft tissue into the bone, which is what often leads to amputation: More than 66,000 amputations were performed on persons with diabetes last year.
Dry, itchy skin
A less dangerous but highly vexing and common side effect of high blood glucose is dry, itchy skin. Dry skin can be linked to high blood glucose in a few different ways. The first is excessive urination, which can actually dehydrate you to the point that your skin tissues begin drying out.
The second greatest cause of dry, itchy skin is poor blood circulation. In fact, skin problems on the feet and lower legs are a sign of atherosclerosis — hardening and narrowing of the arteries and its attendant reduction in circulation — a disease all too common in people with diabetes.
Last but not least, nerve damage can interfere with the normal operation of sweat glands, affecting one of skin’s natural moisturizers and leading to dry skin.
Another skin condition linked to high blood glucose is called diabetic dermopathy. Unique to people with diabetes, diabetic dermopathy shows up as scaly circular or oval patches of discolored skin that resemble age spots. The patches are caused by damage to capillaries from high blood glucose. Diabetic dermopathy is not considered dangerous, and there is no treatment for it, but it serves as a visual sign of high blood glucose.
Speaking of dryness, blurry vision from acute high blood glucose is also a result of the dehydrating effect of excessive urination. As you will recall, when the concentration of glucose in the blood is high, the body attempts to dilute the blood by pulling fluid from cells into the bloodstream. This effect happens throughout the body, including in the cells of the eyes. When the lens of the eye gets dried out, it becomes temporarily warped, and the eye loses its ability to focus properly.
Chronic high blood glucose, on the other hand, can lead to retinopathy, or damage to the back of the eye that can affect vision and ultimately even lead to blindness. Recent research has shown that by the time of diagnosis, 35% of people with Type 2 diabetes already have some degree of retinopathy. This is because in most cases, people with Type 2 diabetes have elevated blood glucose levels for an extended period before their diabetes is diagnosed. This is also why the American Diabetes Association recommends that people with Type 2 diabetes have an initial dilated and comprehensive eye exam shortly after diagnosis.
Headaches and difficulty concentrating
Acute hyperglycemia can cause headaches and difficulty concentrating in a fashion similar to polyphagia — in which starving cells send out hunger signals because they can’t access the glucose circulating in the blood.
Your brain is the biggest glucose hog around. If you don’t believe it, consider that while the brain represents about 2% of your body weight, it devours fully 25% of the glucose you consume. And when brain cells have difficulty getting the fuel they need, they function poorly. This can cause problems with thinking, reasoning, and remembering, difficulty staying focused on tasks, and headaches.
Chronic high blood glucose can also lead to headaches, but by a different route. These headaches are often related to various types of nerve damage. Examples include occipital neuropathy, or damage to the optic nerve from elevated glucose levels, and a variety of diabetic mononeuropathies, which can affect specific cranial nerves, peripheral nerves, or nerve roots — all of which can lead to headaches of varying intensities.