How does diabetes cause ulcers?

How does diabetes cause ulcers?
This question might be in the head of many diabetic patients. Actually diabetes predispose the patient for ulcers. But it does not directly cause ulcers.
You may know that the diabetes cause damage to the peripheral nerves of the patient. Not only diabetes but also alcohol causes this type of damage. This condition is called diabetic or alcoholic peripheral neuritis. Other less significant conditions are tabes dorsalis and syringomyelia.
When peripheral neuritis is present the patient develops glove and stoking type sensory loss. So their peripheries become insensitive to pain and pressure. When one of repeated injury allowed to occur because of lack of appreciation of pain in the area causes trauma and ulcers. These are called neuropathic or trophic ulcers.
Since diabetes also causes vasculitis poor blood supply to these wounds cause delayed healing and sometimes get complicated with bacterial infections.