What is a common characteristic of foot ulcers in diabetic patients?

Foot ulcers in diabetic patients commonly arise from increased pressure on bony prominences due to factors such as neuropathy and poor circulation associated with diabetes. Neuropathy can lead to a lack of sensation in the feet, making patients unaware of injury or pressure, which increases the likelihood of developing ulcers. The bony prominences, such as the metatarsal heads or heel, are particularly susceptible to pressure, especially when combined with inappropriate footwear or poor foot care. This combination of diminished sensation and increased mechanical stress often results in ulceration, making option C the most accurate characteristic.

In contrast, the assertion that foot ulcers are always painful does not hold true, as many diabetic patients do not experience pain due to neuropathy affecting their sensation. The claim that ulcers are usually located on the heel does not encompass the broader range of locations where diabetic ulcers can occur, such as the toes or the balls of the foot. Lastly, diabetic foot ulcers typically do not heal quickly. Healing can be prolonged due to factors such as poor blood flow and the presence of underlying conditions, making quick healing an inapplicable characteristic in this context.