After a long drive I have a swollen midfoot, pebble‑like pain under the second toe, transient erythema with pressure, and a callus between the first and second metatarsal heads; what is the likely diagnosis and recommended management?

Likely Diagnosis: Morton's Neuroma with Secondary Metatarsalgia

Based on your constellation of symptoms—pebble-like pain under the second metatarsal head, transient erythema with pressure, callus formation between the first and second toe, and worsening pain when barefoot—you most likely have Morton's neuroma (interdigital neuroma) with secondary metatarsalgia and increased plantar pressure.

Clinical Reasoning

Your symptoms are classic for Morton's neuroma:

• "Walking on a pebble" sensation is the pathognomonic symptom of Morton's neuroma, caused by fibrous enlargement of the interdigital nerve branches between metatarsal heads 1, 2
• Pain localized to the ball of the foot under the second toe fits the typical distribution, as Morton's neuroma most commonly affects the third interspace but frequently involves the second interspace as well 3, 2
• Transient erythema with pressure that immediately resolves indicates localized inflammation and increased plantar pressure at the metatarsal head, a high-risk sign for tissue breakdown 4
• Callus formation between the first and second metatarsal heads represents a compensatory response to chronic excessive pressure and altered biomechanics, which both predisposes to and results from the underlying nerve pathology 4
• Worsening pain when barefoot occurs because cushioned footwear normally redistributes plantar pressure away from the affected metatarsal heads 4, 5

The midfoot swelling after prolonged driving likely represents reactive edema from sustained pressure in a fixed position, exacerbating the underlying nerve compression 1.

Immediate Management Algorithm

Step 1: Footwear Modification (Start Today)

• Stop walking barefoot immediately—this is the single most important intervention to reduce direct pressure on the inflamed nerve and metatarsal heads 4, 5
• Wear well-fitted athletic shoes or walking shoes with thick cushioned soles that redistribute pressure away from the metatarsal heads 4
• Avoid high heels, pointed-toe shoes, and thin-soled footwear, as these concentrate pressure on the forefoot and can worsen nerve compression 2, 6

Step 2: Callus Debridement

• Schedule urgent debridement with a podiatrist or trained foot care specialist who can use a scalpel to remove the callus between your first and second metatarsal heads 4
• Callus removal is essential because the thickened tissue increases local pressure, perpetuates the cycle of nerve irritation, and can lead to underlying tissue breakdown 4
• Do not attempt self-debridement—improper technique can cause skin injury and increase infection risk 4

Step 3: Pressure Offloading

• Obtain metatarsal pads or custom orthotic inserts that shift weight away from the affected metatarsal heads and reduce nerve compression 6
• Consider over-the-counter gel metatarsal cushions as an immediate temporary measure while awaiting professional orthotic fitting 4

Step 4: Diagnostic Confirmation

If symptoms persist beyond 2–4 weeks despite conservative measures, seek formal evaluation:

• Clinical examination should include the thumb-index finger squeeze test, Mulder's click test, and foot squeeze test to reproduce your symptoms and confirm the diagnosis 1, 6
• Ultrasound imaging is the preferred initial diagnostic modality because it allows real-time dynamic assessment during provocative maneuvers and can identify the exact location and size of the neuroma 1, 6
• MRI can be used if ultrasound is inconclusive or if alternative diagnoses (stress fracture, capsulitis, synovitis) need to be excluded 1, 6

When Conservative Management Fails

If your symptoms do not improve after 6–8 weeks of footwear modification, callus debridement, and orthotic use:

Second-Line: Ultrasound-Guided Corticosteroid Injection

• Local injection of corticosteroid plus anesthetic into the affected webspace under ultrasound guidance can provide significant symptom relief 1, 6
• This is typically performed by a podiatrist, sports medicine physician, or interventional radiologist 1

Third-Line: Surgical Neurectomy

• Surgical excision of the neuroma through a dorsal approach is the definitive treatment when conservative measures and injections fail 3, 2, 6
• Success rates are high (70–85%) when performed for correct indications with proper surgical technique 2, 6

Critical Pitfalls to Avoid

• Do not ignore the callus—it is both a marker of excessive pressure and a contributor to ongoing nerve irritation; failure to address it will result in treatment failure 4
• Do not continue walking barefoot or in thin slippers—this perpetuates the mechanical trauma causing your symptoms 4, 5
• Do not delay seeking care if erythema persists or worsens—persistent redness can indicate impending skin breakdown, especially if you have undiagnosed diabetes or peripheral neuropathy 4
• Rule out diabetes—your symptom pattern (neuropathic pain, callus formation, midfoot swelling) warrants screening for diabetes with fasting glucose or HbA1c, as diabetic neuropathy can coexist with or mimic Morton's neuroma 4

Red Flags Requiring Urgent Evaluation

Seek immediate medical attention if you develop:

• Persistent erythema lasting >24 hours after removing pressure 4
• Warmth, drainage, or fever—these suggest infection 4
• Numbness or tingling extending beyond the second toe—this may indicate more widespread neuropathy requiring workup 4, 7
• Inability to bear weight or severe swelling—consider stress fracture or acute Charcot arthropathy 4