What is the most likely cause of numbness and tingling in the palmar region and digits without wrist pain?

Carpal Tunnel Syndrome (CTS)

Your symptoms of numbness and tingling in the palmar region and digits without wrist pain are most consistent with carpal tunnel syndrome, which is the most common peripheral nerve entrapment affecting 3-6% of adults 1, 2.

Why This Is Most Likely CTS

The classic presentation you're describing—symptoms in the palmar arch and digits without wrist pain—is actually typical for CTS. Here's the key evidence:

• Paresthesia (tingling/numbness) is the most characteristic manifestation of CTS, with the greatest power of association with confirmed median nerve compression 3
• Over 50% of patients with confirmed CTS report tingling or numbness over the whole hand, extending beyond the classic "first 3.5 digits" distribution 4
• Symptoms involving most of the palmar surface of the first three digits are distinctively associated with positive provocative tests (Phalen's and Tinel's) and are not related to neck pain, unlike other causes of hand numbness 5

Important Clinical Nuance

A common pitfall is dismissing CTS because symptoms don't fit the "textbook" median nerve distribution. The evidence shows:

• Sensory symptoms outside the median nerve distribution are common in CTS 4
• Some patients report symptoms proximal to the wrist, though sensory signs on examination don't extend beyond median nerve territory 4
• The absence of wrist pain does not exclude CTS—approximately 6% of confirmed CTS cases have no wrist symptoms at all 3

Next Steps for Diagnosis

Based on the 2024 ACR guidelines 6:

1. Clinical assessment with provocative maneuvers (Phalen's and Tinel's tests) should be performed 1
2. Ultrasound is highly sensitive and specific for CTS diagnosis and can identify space-occupying lesions, anatomic variants, or tendon pathology 6
3. Electrodiagnostic studies (nerve conduction studies/EMG) are indicated if there's diagnostic uncertainty or to determine disease severity before considering surgery 1, 2

Treatment Algorithm

For mild, discontinuous symptoms 1, 2:

• Wrist splinting (cock-up or neutral position) for 6 weeks to 3 months
• Oral corticosteroids as first-line therapy
• Local corticosteroid injections for refractory symptoms

For moderate to severe symptoms 2:

• Surgical evaluation should be considered
• Surgery is indicated if electrodiagnostic studies show significant axonal injury

Key Caveat

While CTS is most likely, other causes should be considered if symptoms don't respond to initial treatment or if examination reveals findings inconsistent with median nerve compression alone 7. However, the combination of palmar and digital paresthesias without wrist pain strongly points toward CTS as your primary diagnosis.