How should I evaluate and treat heel numbness, and when is urgent medical attention required?

Evaluation and Management of Heel Numbness

Heel numbness requires immediate subspecialist referral for neurologic evaluation, including electromyography and nerve conduction studies, as this represents nerve entrapment or compression that can lead to permanent sensory loss if not promptly diagnosed and treated. 1

Initial Assessment: Distinguish Numbness from Other Sensations

• Pure numbness (loss of sensation) indicates neurologic pathology, not mechanical heel pain 1, 2
• Burning, tingling, or numbness together suggest nerve entrapment syndromes such as tarsal tunnel syndrome or Baxter's neuropathy 1, 2, 3
• The presence of numbness distinguishes neurologic causes from mechanical conditions like plantar fasciitis or stress fractures 2, 3

Critical Red Flags Requiring Urgent Evaluation

Immediate Medical Attention Required:

• Complete sensory loss or motor paralysis - may indicate acute nerve compression or limb ischemia 4
• Numbness with increasing swelling, redness, or warmth - especially in diabetic patients, as this may represent infection or Charcot neuroarthropathy 5
• Bilateral numbness with proximal progression - may indicate Guillain-Barré syndrome requiring rapid management 6
• Numbness with severe dysautonomia or predominant motor weakness - suggests systemic neurologic emergency 6

Anatomic Localization Guides Diagnosis

Medial Heel Numbness:

• Tarsal tunnel syndrome - compression of posterior tibial nerve as it courses through the flexor retinaculum, causing medial heel and plantar foot numbness, particularly worsened with prolonged weight bearing 2, 3

Plantar Heel Numbness:

• Baxter's neuropathy - entrapment of the inferior calcaneal nerve (first branch of lateral plantar nerve), often secondary to plantar fasciitis or altered foot biomechanics 7, 8
• Presents with selective numbness in the plantar heel and may show fatty atrophy of abductor digiti minimi muscle on MRI 8

Lateral Heel Numbness:

• Sinus tarsi syndrome - may present with lateral midfoot numbness and instability, particularly with increased activity 3

Diffuse or Poorly Localized Numbness:

• Peripheral neuropathy - typically distal and symmetric, most commonly due to diabetes 1, 6
• Lumbar radiculopathy - requires referral for problems originating in the lumbar spine 1

Diagnostic Workup Algorithm

Step 1: Perform Focused Neurologic Examination

• Test protective sensation using Semmes-Weinstein 5.07 (10-g) monofilament or Ipswich touch test 1
• Add at least one additional assessment: pinprick, temperature, or vibration testing 1
• Assess for motor weakness, particularly in foot intrinsic muscles 8
• Evaluate pedal pulses and vascular status to exclude ischemic causes 1

Step 2: Assess for Underlying Risk Factors

• Diabetes status - obtain history of glycemic control, as distal symmetric polyneuropathy is a major predictor of sensory loss 1
• History of prior ulceration, amputation, or Charcot foot 1
• Recent increase in activity level or change in footwear 1
• History of trauma or ankle sprain 9

Step 3: Order Appropriate Imaging

• Initial radiographs if trauma history or inability to bear weight (Ottawa Ankle Rules) 9
• MRI without contrast is the preferred advanced imaging for nerve entrapment, showing nerve enlargement and fatty atrophy of denervated muscles 8
• Ultrasound can reveal nerve enlargement, hypoechogenic appearance, and space-occupying lesions causing compression 6

Step 4: Refer for Electrodiagnostic Studies

• Electromyography (EMG) and nerve conduction velocity (NCV) studies are essential for confirming nerve entrapment and localizing the lesion 1
• These studies differentiate between focal entrapment neuropathy and systemic polyneuropathy 7

Management Based on Etiology

For Confirmed Nerve Entrapment (Tarsal Tunnel or Baxter's Neuropathy):

• Immediate referral to podiatric foot and ankle surgeon for definitive management 1
• Conservative measures while awaiting specialist evaluation: activity modification, arch supports, and avoiding tight footwear 3
• Ultrasound-guided steroid injection may be considered by specialist for entrapment neuropathy 6
• Surgical decompression has 90-96% success rate for intractable cases of tarsal tunnel syndrome 7

For Diabetic Peripheral Neuropathy:

• Optimize glycemic control to delay progression of neuropathy 1
• Implement comprehensive foot protection program: daily visual inspection, appropriate footwear, and patient education 1
• Patients with loss of protective sensation require inspection at every healthcare visit 1
• Consider pharmacologic treatment for painful neuropathy if present (though not for pure numbness) 1

For Lumbar Radiculopathy:

• Referral required for problems originating in the lumbar spine 1

Common Pitfalls to Avoid

• Never dismiss numbness as "just plantar fasciitis" - numbness indicates neurologic involvement requiring different management 2, 3
• Do not delay referral - chronic nerve compression can lead to permanent sensory loss and muscle atrophy 7, 8
• Avoid corticosteroid injections near the Achilles tendon if posterior heel involvement 1, 9
• Reexamine diabetic patients frequently - those with neuropathy should have feet inspected at every visit, not just annually 1
• Do not rely solely on patient symptoms - patients with advanced neuropathy may not report numbness due to complete sensory loss 1

Patient Education for Those with Confirmed Neuropathy

• Daily foot inspection is mandatory, using a mirror if needed to visualize the heel 1
• Never walk barefoot indoors or outdoors 1
• Check inside shoes daily for foreign objects or rough edges 1
• Water temperature must be below 37°C (test with elbow, not foot) 1
• Notify healthcare provider immediately if any skin breakdown, blister, or color change develops 1
• Wear appropriate footwear with adequate cushioning and arch support at all times 1