Numbness of the leg or any other body part is concerning if it involves the entire limb, follows a head injury or comes on suddenly, according to Mayo Clinic. Patients should seek emergency medical attention if their leg numbness meets these criteria.
Common causes of numbness include nerve injury, carpal tunnel syndrome and excessive pressure on the nerves, according to MedlinePlus. Raynaud's phenomenon, lack of blood supply, insect or spider bites and certain vitamin deficiencies, including B12 deficiency, can also cause numbness. Serious causes of numbness include stroke, seizures, diabetes and transient ischemic attack, also known as mini-stroke. For recurring numbness of the leg or any other body part, seek medical attention.