Left Arm & Armpit Tingling: Causes & When to See a Doctor

Tingling (paresthesia) in the left arm and axilla can arise from neurological, musculoskeletal, cardiovascular, or systemic causes. Always consider cardiac etiology first.

Potential Causes

Category	Conditions	Key Features
Cardiac	Angina, MI, pericarditis	Chest pressure, dyspnea, diaphoresis, radiation to jaw/back; urgent
Cervical Spine	C6–C7 radiculopathy, disc herniation, stenosis	Neck pain, radiation to thumb/index (C6) or middle finger (C7), worsened by neck movement
Brachial Plexus	Thoracic outlet syndrome (neurogenic), Pancoast tumor	Medial arm/ulnar distribution; worse with arm elevation
Peripheral Nerve	Ulnar neuropathy (cubital tunnel), median (carpal tunnel), radial	Specific digit patterns; nocturnal symptoms
Systemic	Diabetic neuropathy, B12 deficiency, hypothyroidism, alcohol, chemo	Stocking-glove, symmetric; other systemic signs
Musculoskeletal	Scalene spasm, pectoralis minor syndrome, rotator cuff tear	Reproducible with movement/palpation
Dermatomal	Herpes zoster (shingles)	Painful vesicular rash in dermatome; can precede rash

Red Flags → Immediate ER

• Chest discomfort, shortness of breath, diaphoresis, syncope
• Sudden weakness, speech difficulty, facial droop (stroke)
• Progressive numbness/weakness

Workup

ECG, troponin, cervical MRI, EMG/NCS, blood glucose, B12, TSH, inflammatory markers.