What are the potential causes and treatment options for a patient with a burning sensation in the hind foot, possibly related to underlying conditions such as diabetes, peripheral neuropathy, or infection?

Burning Sensation in the Hind Foot

A burning sensation in the hindfoot most commonly indicates peripheral neuropathy, particularly diabetic peripheral neuropathy if diabetes is present, and requires immediate assessment for glycemic control, vitamin B12 deficiency, and signs of infection to prevent progression to ulceration and amputation.

Immediate Assessment Priorities

Screen for Diabetes and Metabolic Causes

• Check hemoglobin A1c or fasting glucose immediately, as diabetic peripheral neuropathy is the most common cause of burning foot symptoms 1, 2
• Measure vitamin B12 levels, as deficiency is a reversible cause of neuropathic symptoms 1, 2
• Assess blood pressure and body mass index, as hypertension and obesity are modifiable risk factors for neuropathy development 2

Rule Out Infection Urgently

• Examine for signs of foot infection including local pain, periwound erythema, edema, purulent discharge, or foul odor, as untreated infection can lead to amputation 3
• Maintain high suspicion even with subtle presentations, since peripheral neuropathy and peripheral arterial disease may mask typical infection signs 3
• Check for systemic inflammatory response: temperature >38°C or <36°C, heart rate >90/min, respiratory rate >20/min, white blood cell count >12,000 or <4,000/mcL 3
• If infection is suspected, initiate prompt antibiotic therapy and consider referral to an interdisciplinary care team 3

Assess Vascular Status

• Palpate pedal pulses and measure ankle-brachial index (ABI), as peripheral arterial disease with ABI <0.9 can cause burning symptoms 4
• If ABI is falsely elevated due to arterial calcification (common in diabetes), obtain toe pressure measurements or transcutaneous oxygen pressure 4

Neurological Examination Specifics

Test Protective Sensation

• Use 10-g monofilament testing at multiple plantar foot sites, as loss of protective sensation dramatically increases ulceration risk 1
• Assess small-fiber function with pinprick and temperature sensation testing 1
• Evaluate large-fiber function using 128-Hz tuning fork for vibration and check ankle reflexes 1

Distinguish Neuropathy Patterns

• Burning feet as an isolated symptom can represent hereditary sensory neuropathy or early small-fiber neuropathy, even without objective clinical findings 5
• Note that symptoms aggravated by warmth and ameliorated by cooling suggest small-fiber involvement 5
• Consider that non-Swedish-born patients and smokers report burning sensations at twice the rate of Swedish-born patients and non-smokers, independent of HbA1c levels 6

Pharmacologic Pain Management Algorithm

First-Line Treatment (Start Here)

• Initiate pregabalin 50 mg three times daily (150 mg/day), increasing to 100 mg three times daily (300 mg/day) within 1 week based on efficacy and tolerability 7, 2
• Alternative first-line options include gabapentin 300-2400 mg/day, duloxetine 30-60 mg/day, or amitriptyline 1, 2
• Do not exceed pregabalin 300 mg/day for diabetic peripheral neuropathy, as doses above this provide no additional benefit but increase adverse reactions 7

Critical caveat: These medications reduce pain but do not restore sensation to affected extremities 2. Evidence for long-term benefit and safety is lacking 2.

Monitor Treatment Response Objectively

• Perform periodic objective monitoring of medication response, as patients may not obtain desired pain reduction and adverse effects are common 2
• Common adverse reactions include dizziness (21%), somnolence (12%), peripheral edema (9%), and weight gain (4%) at 300 mg/day pregabalin 7
• Discontinuation rates due to adverse reactions are 9% with pregabalin versus 4% with placebo 7

Second-Line Options (If First-Line Fails)

• Consider nortriptyline, imipramine, venlafaxine, carbamazepine, oxcarbazepine, topical lidocaine, or topical capsaicin 2
• Topical capsaicin 0.025%-0.075% cream can be applied 3-4 times daily for 6 weeks, though initial stinging and burning are expected 3
• Avoid opioids for diabetic peripheral neuropathy pain management 2

Non-Pharmacologic Interventions

Footwear and Daily Care

• Wear loose-fitting shoes with roomy cotton socks and padded slippers to avoid pressure points 1
• Inspect inside of shoes daily before wearing to detect potential irritants 1
• Never walk barefoot indoors or outdoors, and never wear shoes without socks 1
• Wash feet daily with soap and water, drying thoroughly between toes to prevent secondary infections 1
• Apply lubricating creams for dry skin, but never between the toes, as moisture increases maceration and infection risk 1

Physical Measures

• Keep feet uncovered in bed, as bedding pressure on toes can worsen symptoms 1
• Soak feet in icy water and massage for temporary relief during acute flares, but limit to 10 minutes at a time, 4 times daily maximum 3
• Walk regularly to improve circulation, but avoid excessive walking or prolonged standing 1

Alternative Modalities

• Consider transcutaneous electrical nerve stimulation (TENS), which is well-tolerated and inexpensive, though benefits are modest 2
• Exercise programs may provide benefit, though evidence quality is low to moderate 2

High-Risk Patient Management

For Patients with Diabetes

• Counsel all diabetic patients with peripheral neuropathy about daily self-foot examination and healthy foot behaviors 3
• Perform biannual foot examination by a clinician for patients with diabetes and peripheral neuropathy 3
• Provide integrated foot care every 1-3 months, including professional foot treatment, footwear assessment, and reinforced education 1
• Consider home foot temperature monitoring to identify early inflammation before ulceration develops 1

Escalation Criteria

• Promptly refer to an interdisciplinary care team if foot ulceration develops or signs of infection appear 3, 1
• Consider nerve conduction studies if presentation is atypical, asymmetric, or rapidly progressive 1
• Refer for vascular consultation if significant ischemia is present on ABI or toe pressure measurements 4

Common Pitfalls to Avoid

• Do not assume burning feet always correlates with HbA1c levels; the association is not consistently demonstrated 6
• Do not overlook infection in diabetic patients with neuropathy, as presentation may be subtle without typical pain or inflammatory signs 3, 8
• Do not continue pregabalin above 300 mg/day for diabetic neuropathy, as higher doses increase adverse reactions without additional efficacy 7
• Do not neglect smoking cessation counseling, as smoking independently increases burning foot symptoms 6
• When discontinuing pregabalin, taper gradually over minimum 1 week to avoid withdrawal symptoms 7