Diabetic foot syndrome

Board exam relevance: in 1 of 105 exam reports · rank 181

Synonyms: diabetic foot, diabetic foot ulcer, DFU, malum perforans, Charcot foot, foot ulcer
Specialty: Internal medicine · Endocrinology & diabetes
Images: Clinical 3 · X-ray 1
Last updated: 10/2026 · Dr. Pascal Bafteh

Contents

Images (4)
Definition
Classification
Occurrence & epidemiology
Aetiopathogenesis
Clinical features
Diagnosis
Keep learning in the app
Further reading (open access)
Cross-references

Images (4)

Diabetic foot syndrome – clinical photo: Diabetic foot ulcer on the sole — Diabetic foot ulcer on the soleImage: Dr. Lorimer (Wikimedia Commons) · CC BY-SA 4.0 · Source

Diabetic foot syndrome – clinical photo: Diabetic ulcer on a toe — Diabetic ulcer on a toeImage: Mark A. Dreyer, DPM, FACFAS (Wikimedia Commons) · CC BY 4.0 · Source

Diabetic foot syndrome – clinical photo: Charcot foot: collapse of the arch with rocker-bottom deformity, swelling and ulcer over the sole — Charcot foot: collapse of the arch with rocker-bottom deformity, swelling and ulcer over the soleImage: Medicalpal (Wikimedia Commons) · CC BY-SA 4.0 · Source

Diabetic foot syndrome – Foot X-ray in 2 planes: Charcot arthropathy with destruction and malalignment at the Lisfranc joint line — Foot X-ray in 2 planes: Charcot arthropathy with destruction and malalignment at the Lisfranc joint lineImage: Hellerhoff (Wikimedia Commons) · CC BY-SA 4.0 · Source

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Definition

Diabetic foot syndrome (DFS) comprises skin changes, ulceration, infection and gangrene of the foot in people with diabetes. It is based on neuropathy and/or peripheral artery disease (PAD) together with increased susceptibility to infection, and can lead to amputation.

Classification

Wagner-Armstrong classification

Wagner grades (depth and extent of the lesion):

Grade 0: no lesion, possibly foot deformity or cellulitis
Grade 1: superficial ulceration
Grade 2: deep ulcer reaching the joint capsule, tendons or bone
Grade 3: deep ulcer with abscess formation, osteomyelitis or infection of the joint capsule
Grade 4: limited necrosis of the forefoot or heel
Grade 5: necrosis of the entire foot

Armstrong stages (additional findings):

A: no infection, no ischemia
B: infection
C: ischemia
D: infection and ischemia

Occurrence & epidemiology

According to the Robert Koch Institute, diabetic foot syndrome was documented in 6.2 % of people with diabetes covered by statutory health insurance in 2013 (women 5.7 %, men 6.6 %); the frequency rises almost linearly with age. In the North Rhine-Westphalia DMP (structured care program) in 2020, 9.6 % of people with type 2 diabetes had an abnormal foot status.

Aetiopathogenesis

Pathogenesis

3 pathogenetic pillars: neuropathy + PAD + infection.
Neuropathic foot: warm + pink + strong pulses + painless.
Ischemic foot: cold + livid + absent pulses.
Charcot foot: neuropathic osteoarthropathy + 'rocker-bottom'.

Sensory neuropathy: pressure points, foreign bodies and minor injuries are not perceived.
Motor neuropathy: muscle atrophy leads to foot deformities such as claw and hammer toes with peak pressures under the metatarsal heads.
Autonomic neuropathy: dry, cracked skin due to absent sweating makes it easier for pathogens to enter.
Macroangiopathy: PAD in diabetes preferentially affects the lower-leg arteries; medial arterial calcification is common.
Microangiopathy and impaired immunity affect wound repair and defense against infection; even minor skin defects can develop into deep, infected ulcers.

Clinical features

Neuropathic ulcer (malum perforans): painless ulcer, often surrounded by callus, at pressure points, typically on the sole under the metatarsal heads; the foot is warm with palpable pulses.
Ischemic ulcer: painful necrosis at the toes, heel or edge of the foot; the foot is cool, pale to livid, with absent pulses. With coexisting neuropathy, ischemic pain may be absent.
Infection: redness, swelling, warmth, discharge; spread to soft tissue and bone up to osteomyelitis. Systemic signs may be absent.
Charcot foot: acutely warm, red, swollen and often only mildly painful foot; later fractures, subluxations and collapse of the foot arch up to rocker-bottom deformity.
Gangrene: dry or wet-infected, localized at the toes or heel up to the entire foot.

Diagnosis

Inspection of both feet: skin, callus, fissures, nails (onychomycosis), hair loss, deformities, ulcers with location, size and depth; footwear
Neurological status: pressure sense with a 10 g monofilament, vibration sense, pain and temperature sensation, ankle reflexes
Perfusion: foot pulses, ankle-brachial index (falsely high with medial arterial calcification), additionally toe pressure or toe-brachial index, transcutaneous oxygen tension and color duplex ultrasound
Infection and bone: probing to bone (probe-to-bone test), wound swab or tissue sample to identify pathogens, foot x-ray, MRI if osteomyelitis or Charcot foot is suspected
Laboratory: inflammatory markers, glucose metabolism and kidney function

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