Many conditions can cause tingling in the left arm. According to the MedlinePlus website, tingling sensations in the body, especially the extremities, may indicate a serious underlying health problem, or the tingling may be a temporary phenomenon that resolves itself over time. Tingling sensations in the arm may be caused by certain musculoskeletal conditions, nerve-related disorders or blood vessel disorders. Tingling in the upper extremity can also be caused by substance abuse and certain chronic diseases.
A myocardial infarction, also known as a heart attack, is a potentially life-threatening cause of left arm tingling. According to the Cleveland Clinic, myocardial infarction is one of the leading causes of death worldwide. Myocardial infarction occurs when blood flow to the heart is impaired, causing heart muscle tissues to experience ischemia or a lack of oxygen. Without sufficient oxygen, the myocardial cells or heart muscle tissue begins to die. Common signs and symptoms associated with myocardial infarction include tingling sensations in the jaw, teeth, shoulder, left arm and back, chest pain that feels like pressure, fullness or squeezing, dyspnea or shortness of breath, excessive sweating, fainting and an inability to think clearly. The Cleveland Clinic says certain risk factors may increase the likelihood of a myocardial infraction--including a family history of coronary artery disease, hypertension and smoking.
Thoracic Outlet Syndrome
Thoracic outlet syndrome is a common musculoskeletal cause of left arm tingling. The National Institute of Neurological Disorders and Stroke, or NINDS, says thoracic outlet syndrome occurs when nerves or blood vessels are compressed as they travel though the narrow opening from the base of the neck to the axilla or armpit and arm. Numerous factors can compress structures in the area of the thoracic outlet, including extra ribs, poor posture, trauma, overuse or repetitive strain injuries, obesity and pregnancy. Possible signs and symptoms associated with thoracic outlet syndrome include numbness and tingling in the affected-side arm and hand, pain in the neck and shoulder, an aching sensation in the arm and hand, decreased grip strength, hand discoloration, throbbing near the clavicle or collarbone and arm swelling. According to the NINDS, the prognosis or outlook for this condition varies between individuals.
Carpal Tunnel Syndrome
Carpal tunnel syndrome, common among office workers, can cause tingling in the left arm, wrist and hand. According to MayoClinic.com, the carpal tunnel is a narrow passageway through which the median nerve--one of the largest nerves in the upper extremity--and nine tendons pass. The carpal tunnel is situated on the palm side of the wrist and is bound by bone and fibrous tissue. Anything that compresses the median nerve in the carpal tunnel can cause carpal tunnel syndrome. Common signs and symptoms associated with carpal tunnel syndrome include tingling and numbness in the affected-side forearm, wrist and hand; wrist pain that radiates up to the shoulder and into the palm and fingers; the sensation of hand weakness; and the tendency to drop objects. MayoClinic.com says improving posture and taking frequent breaks when working on the computer can help prevent carpal tunnel syndrome.