Understanding diabetic foot ulcers: causes, stages, and warning signs
What a diabetic foot ulcer is, why it develops, how clinicians grade severity, and the early signs worth acting on.
A diabetic foot ulcer (DFU) is an open wound, usually on the sole or side of the foot, that develops in people with diabetes. This article is general education, not medical advice — always consult a licensed physician about your own situation.
Why they develop
Two long-term effects of diabetes combine to make the foot vulnerable: reduced sensation (neuropathy), so minor injuries go unnoticed, and reduced circulation (peripheral arterial disease), so wounds heal slowly. High blood sugar further slows healing and raises infection risk.
How severity is described
Clinicians often use grading systems (such as the Wagner scale) that range from intact-but-at-risk skin through superficial ulcers to deep wounds involving tendon, bone, or widespread infection. Grading guides which specialists and treatments a case needs.
Early warning signs
- A blister, callus, or sore that is slow to heal
- Redness, warmth, swelling, or drainage
- New numbness, tingling, or changes in foot shape
Early review by a specialist team gives the widest range of options. If you notice these signs, seek assessment promptly from a qualified clinician.