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Diabetic foot is a condition that results from long-standing diabetes and comprises ulcers, infections, and foot deformities. These complications result from the effects of diabetes on the peripheral nervous system and microvasculature; once one complication (e.g., ulceration) develops, the likelihood of developing another (e.g., osteomyelitis) increases. Diagnosis and management depend on the specific complication, but usually involve assessment for associated neuropathy and peripheral arterial disease (PAD), involvement of a multidisciplinary foot care team, and optimization of diabetes management. All patients should be educated on prevention of diabetic foot, e.g., daily foot examinations, foot care, and glycemic control, and encouraged to attend scheduled diabetic foot screenings.
See also “Diabetic neuropathy.”
- Up to one-third of patients with diabetes develop foot ulcers. 
- Associated with increased rates of: 
Risk factors 
- Poor glycemic control: Chronic hyperglycemia causes nonenzymatic glycation of axon proteins and subsequent development of progressive sensorimotor neuropathy, typically affecting multiple peripheral nerves.
- Long-term comorbidities
- Microvascular disease (e.g., retinopathy, chronic kidney disease)
- Diabetic foot deformities and calluses
- Prior ulcers or amputation
- Dermatological conditions, e.g., fungal infections
Diabetic foot ulcers are classified as: 
- Neuropathic ulcers: due to neuropathy (e.g., peripheral sensory neuropathy, autonomic neuropathy)
- Ischemic ulcers: due to PAD and microvascular changes 
- Neuroischemic ulcers: due to both neuropathy and ischemic changes
Clinical features 
- Skin breakdown with or without surrounding tissue necrosis 
- Usually painless
- May be preceded by signs of infection, trauma, or calluses
- Underlying risk factors may be present, e.g.:
- (e.g., sensory loss, motor weakness)
- (e.g., cool foot with no palpable pulses)
- Assess for any signs of diabetic foot infection.
- Evaluate for peripheral neuropathy (see “Diagnostics of polyneuropathy”).
- Perform . 
- Consider imaging for underlying diabetic foot osteomyelitis.
Management of diabetic foot ulcers 
- Management of underlying causes
Specialized footwear 
- Provide mechanical offloading from pressure points 
- Reduce progression and recurrence of foot ulcers
- Decrease calluses
- Wound care: Provide in consultation with a wound care specialist.
- Refractory ulcers: little response after at least 4 weeks of therapy 
- Follow up with patients at 1–4 week intervals to assess healing progress. 
- Patients should be followed up for life by foot care specialists (see “Prevention of diabetic foot”). 
- Infection occurs in ∼50% of diabetic foot ulcers. 
- Infection is a main risk factor for amputation in patients with diabetes. 
- Infections are typically polymicrobial.
- Staphylococci and streptococci spp. are the most common causative pathogens.
Clinical features 
- Signs and symptoms
- Classification of infection severity 
- CBC, CRP, ESR 
- Wound cultures via biopsy or curettage
- diagnostics of polyneuropathy. and
- Assessment for diabetic foot osteomyelitis (e.g., probe to bone test, imaging)
- Patients with severe infections: Additionally obtain diagnostic studies for sepsis.
- Refer patients to a multidisciplinary foot care team when possible. 
- Admit patients with any of the following criteria:
- Severe infection
- Little response to outpatient management
- Start wound care; patients may require surgical debridement or in severe cases, amputation.
Initiate . 
- Consider the following factors when choosing an antibiotic:
- Route 
- Adjust antibiotic therapy as needed based on culture results and continue for up to 4 weeks. 
Diabetic foot osteomyelitis 
- Common in patients with malum perforans ulcers
Osteomyelitis should be suspected in any patient with an ulcer and any of the following features: 
- Clinical features of skin and soft tissue infection (e.g., erythema, edema)
- Ulcer size > 2 cm2 and/or ulcer depth > 3 mm 
- Exposed bone tissue
- Positive probe-to-bone test
- Chronic (lasting several weeks) and/or treatment-resistant ulcers
- An ulcer overlying a bony prominence
- Markedly increased ESR (> 70 mm/hour)
- Unexplained leukocytosis
- Obtain serial plain radiographs and/or MRI (see also “Diagnostics of osteomyelitis”). 
- Treatment involves optimizing the management of diabetes, antibiotics, and possible surgery (see “Treatment of osteomyelitis”). 
Hammer toes and claw toes 
See also “Toe deformities.”
- Pathophysiology: occurs secondary to diabetic neuropathy due to loss of intrinsic muscle volume and thickening of the plantar aponeurosis 
- Clinical features 
- Management: Refer to a foot care specialist. 
Diabetic neuropathic arthropathy (Charcot foot) 
- Neuropathic arthropathy is the development of bone destruction, subluxation/dislocation, and deformity secondary to neuropathy (most commonly diabetic neuropathy).
- The tarsus and tarsometatarsal joints are most commonly affected.
- Clinical presentation depends on the stage.
- Diagnosis requires x-ray (first line) and MRI (in diagnostic uncertainty).
- Initial treatment is conservative (mechanical offloading, treatment of diabetes); surgery is used for severe or refractory cases.
- Address risk factors for diabetic foot ulcers, e.g.: 
- Educate patients (or caregivers) on: 
- The importance of attending regular diabetic foot screenings
- Daily self-monitoring, including:
- Avoiding self-treatment of calluses/corns (e.g., chemical removal agents); patients should see a healthcare professional.
- Selecting socks with no seams, or wearing socks with seams inside out to prevent rubbing
Choosing appropriate footwear
- Avoid walking barefoot or wearing open-toed or open-heeled shoes.
- Ensure shoes fit properly and meet the criteria for safe footwear.
- Patients at high risk of ulceration require specialized therapeutic footwear.
- and how to seek appropriate medical attention for them
Patients with other microvascular complications (e.g., diabetic retinopathy, peripheral neuropathy) may struggle to perform daily foot care; teach caregivers to examine the foot if there are concerns about the patient's ability to self-monitor. 
Screening for diabetic foot 
- Interval 
- Focused history to determine if, since their last visit, there have been any new:
- Inspection of the skin (e.g., assessing for skin breakdown, calluses, )
- Evaluation of bones (e.g., for deformities)
- (e.g., 10g monofilament test)