15 Arm and Leg Asymmetries That Prompt Neurological Evaluation

10. Temperature and Circulatory Asymmetries - Autonomic and Vascular Considerations

Asymmetrical temperature differences, color changes, or circulatory abnormalities between corresponding limbs can indicate neurological pathology affecting autonomic nervous system function, sympathetic innervation, or central nervous system control of vascular regulation. These findings may manifest as one limb feeling consistently cooler or warmer than its counterpart, displaying different coloration ranging from pallor to cyanosis or erythema, or showing differences in sweating patterns that suggest autonomic dysfunction. Complex regional pain syndrome (CRPS) often presents with dramatic asymmetries in temperature, color, and sweating between affected and unaffected limbs, typically following trauma or surgery and involving both peripheral and central sensitization mechanisms. Sympathetic nervous system dysfunction, whether due to peripheral nerve injury, spinal cord pathology, or central nervous system lesions, can cause asymmetrical autonomic symptoms including temperature dysregulation, altered sweating patterns, and trophic skin changes. Stroke affecting areas of the brain involved in autonomic control may cause subtle but detectable differences in skin temperature and circulation between the affected and unaffected sides, often accompanying other neurological deficits. Peripheral neuropathies, particularly those affecting small fiber nerves responsible for autonomic function, can cause asymmetrical temperature sensation abnormalities and altered vascular responses that may be early indicators of progressive neuropathic processes. The evaluation of temperature and circulatory asymmetries requires careful examination of skin color, temperature, moisture, and trophic changes, along with assessment of peripheral pulses and capillary refill times. Quantitative sudomotor axon reflex testing (QSART) and other autonomic function tests can provide objective measurements of sympathetic nervous system function, while thermography may document temperature asymmet