What is the differential diagnosis (Ddx) for a burning sensation localized to the radial area of the palmar surface on one side?

Differential Diagnosis for Burning Sensation Localized to Radial Palm

The most likely diagnosis for a burning sensation strictly localized to the radial palmar surface is superficial radial nerve neuropathy (Wartenberg syndrome) or a palmar cutaneous branch injury of the median nerve, with the key distinguishing feature being that radial nerve involvement spares the fingers and dorsum while median nerve palmar cutaneous branch injury may extend slightly more proximally into the wrist crease. 1, 2

Primary Differential Diagnoses

Superficial Radial Nerve Sensory Branch Neuropathy (Wartenberg Syndrome)

• The superficial radial nerve provides cutaneous innervation to the radial aspect of the palm and can be compressed or injured without motor involvement 1, 2
• This presents as burning, tingling, or dysesthesias strictly in the sensory distribution without weakness since the superficial branch is purely sensory 3, 2
• Compression typically occurs at the wrist or distal forearm where the nerve becomes superficial, often from tight watchbands, handcuffs, or repetitive wrist movements 3, 4
• The hallmark is that symptoms are confined to the radial palm and do not involve the dorsal hand or fingers, which helps distinguish it from more proximal radial nerve lesions 1, 2

Palmar Cutaneous Branch of Median Nerve Injury

• The palmar cutaneous branch of the median nerve arises proximal to the carpal tunnel and provides sensation to the radial palm 5
• This branch can be injured during carpal tunnel surgery, wrist trauma, or laceration without causing carpal tunnel syndrome symptoms in the fingers 5
• Burning pain localized to the thenar eminence and radial palm without finger involvement suggests this diagnosis 5

Partial Median Nerve Injury (Thenar Branch)

• Isolated injury to sensory fibers of the median nerve at the wrist level can cause radial palm burning 5
• However, typical median nerve compression (carpal tunnel syndrome) would involve the radial three digits, which your description excludes 5

Secondary Considerations

Complex Regional Pain Syndrome (CRPS) Type II

• Following trauma or surgery to the hand/wrist, CRPS can present with burning pain in a localized distribution 6
• Associated features include allodynia, temperature changes, and color changes in the affected area 6
• This diagnosis requires a history of inciting trauma or injury 6

Small Fiber Neuropathy

• Can present with burning dysesthesias in a localized distribution 7
• More commonly affects distal extremities bilaterally, but can be unilateral and focal 7
• Associated with diabetes, autoimmune conditions, or may be idiopathic 7

Critical Diagnostic Approach

Essential History Elements

• Timing and onset: Acute onset suggests trauma or compression; gradual onset suggests chronic entrapment 3, 2
• Trauma history: Recent wrist injury, surgery (especially carpal tunnel release), lacerations, or fractures 5, 6, 4
• Compression history: Tight jewelry, handcuffs, repetitive wrist movements, or prolonged pressure 3, 4
• Associated symptoms: Weakness (suggests motor involvement), finger symptoms (suggests more proximal lesion), or dorsal hand involvement (suggests different nerve distribution) 1, 2

Physical Examination Findings

• Sensory testing: Map the exact distribution using light touch, pinprick, and two-point discrimination to determine which nerve territory is affected 5
• Tinel's sign: Percussion over the superficial radial nerve at the wrist or over the palmar cutaneous branch may reproduce symptoms 3, 2
• Motor examination: Test thumb abduction (median nerve), wrist/finger extension (radial nerve motor branch), and grip strength to exclude motor involvement 1, 2
• Provocative maneuvers: Wrist flexion/extension, forearm pronation with wrist ulnar deviation (Finkelstein-like maneuver) may reproduce radial sensory nerve symptoms 3, 2
• Inspection: Look for surgical scars, evidence of trauma, color changes, or swelling suggesting CRPS 5, 6

Diagnostic Testing Strategy

• Initial imaging: Radiographs of the hand and wrist to exclude fracture, arthritis, or bony abnormality as the initial study 5
• Advanced imaging if indicated: MRI of the wrist without contrast if clinical examination suggests soft tissue mass, tumor, or unclear etiology 5
• Electrodiagnostic studies: Nerve conduction studies and EMG can confirm radial or median nerve involvement and localize the lesion, though purely sensory branch lesions may show normal motor studies 2
• Ultrasound: High-resolution ultrasound can visualize the superficial radial nerve and identify compression sites or neuromas 5

Management Algorithm

Conservative Management (First-Line for 3-6 Months)

• Activity modification: Avoid repetitive wrist movements and remove compressive items (watches, bracelets) 3, 2
• Splinting: Neutral wrist splint to reduce nerve tension, particularly at night 3
• Anti-inflammatory measures: NSAIDs for 2-4 weeks if inflammation is suspected 3
• Neuropathic pain medications: Gabapentin starting at 300mg at bedtime, titrating to 900-3600mg daily in divided doses for burning dysesthesias 8
• Physical therapy: Nerve gliding exercises to encourage mobility and reduce adhesions 3

Surgical Intervention Indications

• Failure of conservative management: No improvement after 3-6 months of appropriate conservative treatment 3, 2
• Progressive weakness: Any motor involvement suggests need for earlier surgical evaluation 3, 2
• Space-occupying lesion: Tumor, ganglion cyst, or other mass identified on imaging 3, 4
• Traumatic nerve injury: Laceration or complete disruption requiring repair 6, 4

Surgical Approach

• Decompression of the superficial radial nerve or neurolysis of the palmar cutaneous branch depending on the identified lesion 3, 2
• Early active motion post-operatively to encourage nerve gliding 3
• Results are less favorable than carpal or cubital tunnel release, with worst outcomes in work-related injuries and chronic pain patients 3

Common Pitfalls to Avoid

• Misdiagnosing as tendonitis: Radial nerve compression successfully masquerades as tendonitis or tendon rupture because sensory complaints may be subtle 3
• Overlooking associated neuropathies: There is a relatively high incidence of compressive neuropathy involving other major nerves in the same extremity 3
• Premature surgery: Patients with poor localization of symptoms on physical examination have worse surgical outcomes 3
• Missing space-occupying lesions: Spontaneous onset of dense symptoms is often due to tumors or masses in the forearm/wrist requiring imaging 3, 4
• Inadequate trial of conservative management: Surgery should only be considered after several months of splinting, anti-inflammatory medication, and activity modification have failed 3, 2