"Pins and needles," also known as paresthesia, is caused by prolonged pressure on a particular nerve, states the National Institute of Neurological Disorders and Stroke. Temporary paresthesia in the left arm is typically caused by putting pressure on a nerve in or connected to the left arm.
Paresthesia is often temporary, caused by leaving a limb in an awkward position for too long, putting undue pressure on a nerve. If the paresthesia is long-lasting, a more serious condition may be present, reports the National Institute of Neurological Disorders and Stroke.
Chronic paresthesia is less frequent, and may be a sign of a more serious condition. Traumatic nerve damage, stroke and different neurological disorders are known to cause chronic paresthesia, explains the National Institute of Neurological Disorders and Stroke. Vascular lesions and tumors, if they put pressure on a nerve, may cause chronic paresthesia.
Orthopedic issues can also cause paresthesia, according to Healthgrades. Broken bones, degenerative disk disease, osteoporosis, a herniated disk, carpal tunnel syndrome, back injuries or neck injuries are all possible causes of paresthesia. Other neurological conditions that are potential causes of paresthesia include pernicious anemia caused by vitamin B-12 deficiency, lead poisoning, peripheral neuropathy, brain tumors and alcoholism, states Healthgrades.