What are the causes and treatments of tingling sensation in the foot?

Tingling in the Foot: Causes and Treatment

Most Common Causes

Diabetic peripheral neuropathy is the leading cause of foot tingling, affecting up to 50% of diabetic patients, and should be screened for first even in younger adults without known diabetes. 1, 2

Primary Etiologies to Consider:

• Diabetic neuropathy: Small fiber involvement produces burning, tingling, and painful dysesthesias starting in the toes, often worse at night 2
• Vitamin B12 deficiency: Can cause sensory neuropathy with tingling 1, 2
• Peripheral arterial disease: Produces numbness particularly with exertion, described as fatigue or aching 2
• Nerve entrapment syndromes: Including tarsal tunnel syndrome or Baxter's neuropathy (inferior calcaneal nerve) causing burning heel pain 3
• Alcohol-related neuropathy: From chronic alcohol use 1
• Medication-induced neuropathy: Neurotoxic medications 1

Initial Clinical Assessment

History Elements to Elicit:

• Duration and pattern: Determine if symptoms are constant versus intermittent, and if related to activity or rest 2
• Symptom characteristics: Burning sensations indicate small fiber involvement; pure numbness suggests large fiber involvement 1
• Risk factor screening: Diabetes history, alcohol use, vitamin deficiencies, family history of neuropathy, medications, autoimmune conditions 2
• Bilateral versus unilateral: Bilateral presentation suggests systemic disease rather than focal compression 2

Physical Examination Protocol:

Perform a comprehensive neurological foot examination including small fiber, large fiber, and protective sensation testing: 1, 2

• Small fiber function: Pinprick sensation and temperature sensation testing in both feet, particularly the toes 1, 2
• Large fiber function: Vibration testing with 128-Hz tuning fork at the dorsal aspect of the hallux, moving proximally until threshold detected 1
• Ankle reflexes: Assessment for diminished or absent reflexes 1
• 10-g monofilament testing: At multiple plantar sites to assess protective sensation and ulcer risk 1, 2
• Vascular assessment: Palpation of dorsalis pedis and posterior tibial pulses 1

Diagnostic Workup

Laboratory Testing (Order First):

• Hemoglobin A1c or fasting glucose: Screen for diabetes, the most common cause even in young adults 2
• Vitamin B12 level: Deficiency causes sensory neuropathy 1, 2
• Thyroid function tests: Hypothyroidism can cause neuropathy 2
• Complete blood count: Screen for anemia or hematologic disorders 2
• Comprehensive metabolic panel: Assess renal function and electrolytes 2

When Imaging is Indicated:

Imaging is NOT routinely indicated unless specific red flags are present. 2, 3

• Plain radiographs: Only if history of trauma, inability to bear weight, or point tenderness over bony structures per Ottawa Ankle Rules 2, 3
• MRI foot without contrast: Reserved for suspected nerve entrapment (demonstrates denervation changes in abductor digiti minimi for Baxter's neuropathy) or when diagnosis remains unclear 3

Electrodiagnostic Testing:

EMG/nerve conduction studies are rarely needed except when clinical features are atypical or diagnosis remains unclear after initial workup. 1, 2

Treatment Algorithm

Address Underlying Causes:

• Diabetes management: Tight glycemic control is the only strategy convincingly shown to prevent or delay diabetic peripheral neuropathy in type 1 diabetes and slow progression in type 2 diabetes 1
• Vitamin B12 supplementation: If deficiency identified 2
• Thyroid replacement: If hypothyroidism present 2

Symptomatic Pain Management:

For neuropathic pain, pregabalin, duloxetine, or gabapentin are recommended as initial pharmacologic treatments. 1

Foot Protection Strategies:

• Well-fitted walking shoes or athletic shoes: For patients with neuropathy or evidence of increased plantar pressure 1
• Custom-molded shoes: For extreme bony deformities (e.g., Charcot foot) 1
• Daily foot inspection: Patients with loss of protective sensation must substitute visual inspection for impaired sensation 1

Risk Stratification and Follow-Up

Annual screening is required for all type 2 diabetics and type 1 diabetics after 5 years duration: 1

• IWGDF Risk 1 (LOPS or PAD alone): Screen every 6-12 months 2
• IWGDF Risk 2 (LOPS + PAD, or either with foot deformity/callus): Screen every 3-6 months 2
• IWGDF Risk 3 (history of ulcer/amputation or end-stage renal disease): Screen every 1-3 months 2

When to Refer

• Neurology referral: If symptoms persist beyond 6-8 weeks despite treatment of underlying conditions, for electrodiagnostic studies 2
• Podiatry referral: For custom orthotics and biomechanical assessment if symptoms persist beyond 6-8 weeks 2
• Vascular surgery: For significant peripheral arterial disease symptoms or positive ankle-brachial index 1

Critical Pitfalls to Avoid

• Never assume symptoms are purely mechanical without screening for diabetes, even in young adults without known diabetes 2
• Recognize bilateral presentation as a red flag for systemic disease rather than focal compression 2
• Do not order extensive imaging initially—this is a clinical diagnosis and imaging is low-yield unless red flags present 2, 3
• Do not overlook vitamin B12 deficiency, particularly in patients on metformin or with gastrointestinal disorders 1
• Avoid missing loss of protective sensation, as up to 50% of diabetic peripheral neuropathy may be asymptomatic, placing patients at high risk for foot ulceration 1