Can shoe rubbing cause trauma, especially in individuals with pre-existing conditions such as diabetes or impaired circulation?

Can Shoe Rubbing Cause Trauma?

Yes, shoe rubbing absolutely causes trauma through repetitive shear deformation of skin layers, leading to friction blisters in healthy individuals and potentially catastrophic outcomes including ulceration, infection, amputation, and death in patients with diabetes or impaired circulation. 1

Mechanism of Injury in Healthy Individuals

Friction blisters form through repetitive shear deformation, not simple surface rubbing. The three fundamental elements are: (1) motion of underlying bone, (2) high friction force at the skin-shoe interface, and (3) repetition of these shear events that separate skin layers and allow fluid accumulation. 2

• The traditional paradigm of "heat, moisture, and friction" is outdated—the actual mechanism involves shear forces causing skin components to separate at planes of weakness, creating fluid-filled spaces. 1, 2
• Blisters commonly occur at the heel, forefoot, and toes where repetitive mechanical stress is highest. 3
• In uncomplicated cases, these present as tense, clear fluid-filled elevations with normal-appearing skin at the base and no systemic symptoms. 3

Critical Distinction: High-Risk Populations

Patients with Diabetes

In diabetic patients, seemingly minor shoe rubbing can trigger a cascade leading to amputation or death. 1

The pathophysiology involves three converging factors:

• Peripheral neuropathy prevents recognition of pressure points, rubbing, or developing injuries—loss of protective sensation is present in most diabetic foot complications. 4
• Peripheral arterial disease (PAD) occurs 2-4 times more frequently in diabetic patients and severely impairs wound healing (present in 20-40% of diabetic foot infections). 5, 4
• Infection susceptibility allows minor trauma to progress to deep tissue infection and osteomyelitis. 5, 4

Ill-fitting shoes were identified as one of the three most common origins of external trauma causing diabetic foot ulcers (along with puncture wounds and self-care practices). 1

Documented Outcomes in Diabetic Patients

The consequences of shoe-induced trauma in diabetes are severe:

• Amputation was reported as an outcome in 48.9% of studies examining trauma-induced diabetic foot ulcers. 1
• Mortality was documented in 22.22% of studies, with rates ranging from 3% to 40.4%. 1
• Five-year mortality after diabetic foot ulcer with PAD is approximately 50%, comparable to deadly cancers. 4
• The risk of amputation increases 46-fold when a minor trauma becomes infected in diabetic patients compared to non-diabetic individuals. 1

Most of these traumas occurred in the home environment during everyday activities and were preventable in nature. 1

Patients with Epidermolysis Bullosa (EB)

In EB, shoe rubbing causes immediate blistering due to defective skin adhesion where even minor friction creates skin separation. 1

• Blisters on feet can be caused by dressings, socks, shoes, or boots rubbing against skin, though they sometimes appear spontaneously. 1
• The size of blisters depends on EB subtype and the degree and duration of friction. 1
• Podiatry education programs should be offered from birth to prevent blistering and wounds (Grade B recommendation). 1

Clinical Algorithm for Assessment

Immediate Evaluation Required

When assessing shoe-related foot trauma, systematically evaluate:

1. Patient risk factors:

   • Diabetes status and duration
   • Presence of peripheral neuropathy (loss of protective sensation)
   • Vascular status (check pedal pulses, capillary refill, obtain ankle-brachial index)
   • History of previous foot ulcers or amputations 5, 4

2. Wound characteristics requiring urgent action:

   • Greyish discoloration at wound borders suggests tissue necrosis/severe ischemia—requires vascular assessment and surgical consultation within 24-48 hours. 4
   • Purulent drainage or ≥2 cardinal signs of inflammation (erythema, warmth, tenderness, pain, induration). 5
   • Probe-to-bone test positive (largely diagnostic of osteomyelitis). 5

3. Vascular assessment:

   • ABI <0.5 indicates critical ischemia impairing wound healing. 4
   • Toe pressures <30 mmHg or TcPO2 <30 mmHg identify critical ischemia. 4
   • Critical pitfall: Up to 50% of diabetic foot ulcer patients have PAD despite palpable pulses. 4

Urgent Surgical Consultation Indications

Obtain surgical evaluation within 24-48 hours for: 5, 4

• Deep abscess, extensive bone/joint involvement
• Crepitus or gas in tissues
• Substantial necrosis, gangrene, or greyish tissue
• Necrotizing fasciitis suspected
• Severe lower limb ischemia

Treatment Priorities

For moderate-to-severe infections in diabetic patients:

• Initiate broad-spectrum IV antibiotics immediately covering MRSA, Gram-negative rods, and anaerobes (if extensive necrosis/foul odor). 5
• Obtain cultures before antibiotics via deep tissue specimens. 5
• Plain radiographs immediately; MRI if osteomyelitis suspected. 5
• Aggressive debridement of all necrotic tissue with complete off-loading. 5
• Duration: 1-2 weeks for soft tissue infections, 6 weeks if osteomyelitis without bone resection. 5

Early revascularization improves limb salvage rates to 80-85% at 12 months (versus only 50% without revascularization). 4

Prevention Strategies

For all patients:

• Properly sized footwear is essential—ill-fitting shoes were a common trauma origin across all studies. 1
• Socks that reduce friction and moisture. 6
• Foot conditioning through gradual activity increases. 6

For high-risk patients (diabetes, EB):

• Education programs to recognize and avoid causes of blistering/wounds including footwear selection. 1
• Assessment and monitoring of weight distribution with appropriate cushioning. 1
• Regular foot inspection, particularly for patients with neuropathy who cannot feel developing injuries. 4