Carpal Tunnel Syndrome: This condition is the most common cause of bilateral hand numbness, especially if it involves the thumb, index, and middle fingers. It occurs due to compression of the median nerve at the wrist.

Cervical Radiculopathy: Numbness in the hands can also be caused by nerve root compression in the cervical spine, which can affect multiple nerves and lead to bilateral symptoms.
Peripheral Neuropathy: Conditions like diabetes, vitamin deficiencies, or alcohol abuse can cause peripheral neuropathy, leading to numbness in the hands and feet.
Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib) can cause numbness and tingling in the hands.

Multiple Sclerosis: Although less common, multiple sclerosis (MS) can present with numbness or tingling in various parts of the body, including the hands. MS is an autoimmune disease that affects the brain and spinal cord.
Spinal Cord Compression: Conditions such as tumors, abscesses, or fractures can compress the spinal cord, leading to bilateral numbness, weakness, and potentially severe consequences if not promptly addressed.
Vitamin B12 Deficiency: A deficiency in vitamin B12 can cause neurological symptoms, including numbness in the hands and feet, and if left untreated, can lead to permanent neurological damage.

Guillain-Barré Syndrome: An autoimmune disorder in which the body's immune system mistakenly attacks part of its peripheral nervous system, leading to muscle weakness, and sometimes numbness or tingling, which can be bilateral.
Sjögren's Syndrome: An autoimmune disorder that can cause peripheral neuropathy among other symptoms, leading to numbness in the hands.
Amyloidosis: A condition caused by an abnormal protein (amyloid) that can accumulate in various organs, including nerves, leading to peripheral neuropathy and numbness.