Vascular — Classifying a Diabetic Foot Ulcer by Clinical Features
A 63-year-old woman with type 2 diabetes for 20 years finds a 2 cm ulcer over the lateral border of her left foot, beneath the fifth metatarsal head. She had felt no pain. The ulcer has a red granulating base, a callused edge and serous discharge. Dorsalis pedis and posterior tibial pulses are intact. Which type of ulcer is most likely?
- A.Neuropathic ulcerCorrect
- B.Ischaemic ulcer
- C.Venous ulcer
- D.Marjolin ulcer
Explanation
Diabetic foot ulcers are classified by their principal cause, and the bedside features usually decide it. A painless ulcer at a pressure point such as a metatarsal head, with surrounding callus, a red granulating base and intact pulses, is neuropathic: sensory loss lets repeated pressure from walking or footwear break the skin unnoticed. Healthy granulation tissue itself indicates an adequate blood supply. An ischaemic ulcer, by contrast, is painful, sits at the toe tips, heel or foot margins, has a pale or sloughy punched-out base with little granulation, and occurs in a cool foot with weak or absent pulses. The lateral border of the foot can host both types, so site alone does not settle it; the pulses and granulation do. Venous ulcers lie in the gaiter area above the medial malleolus with oedema, haemosiderin staining and lipodermatosclerosis, not on the sole. A Marjolin ulcer is squamous cell carcinoma arising in a long-standing scar or chronic wound, suggested by rolled everted edges, bleeding or failure to heal over years. The point often missed is that many diabetic ulcers are neuroischaemic, so arterial assessment is still required even when neuropathy is obvious.
Why each option
- A.
- Correct. A painless, callused, granulating ulcer at a metatarsal pressure point with intact pulses is typical of diabetic neuropathy.
- B.
- Ischaemic ulcers are painful, pale and poorly granulating in a cool foot with weak or absent pulses, unlike this ulcer.
- C.
- Venous ulcers occur above the medial malleolus with oedema and skin pigmentation, not beneath a metatarsal head on the foot.
- D.
- Malignant change in a chronic wound causes rolled edges and bleeding after years of non-healing, not a fresh granulating pressure ulcer.
Reference: IWGDF Guidelines on the Prevention and Management of Diabetes-Related Foot Disease (2023), including the IWGDF/IDSA classification guideline; UpToDate — Management of diabetic foot ulcers (2025)
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