A little numbness in the left ear may be caused by local microcirculation disorder, otitis, cerebral blood supply insufficiency and other reasons. 1. Local microcirculation disorder: generally in cold weather is easy to cause microvascular disorder of the ear, due to the blood supply of the ear itself is relatively poor, the blood vessels will be due to cold stimulation and spasm contraction, causing ischemic changes in the left ear, which causes local dysfunction as well as nerve damage, the appearance of numbness in the left ear. 2. Otoneuritis: usually due to cold or fatigue after a viral infection, resulting in inflammation of the peripheral nerves of the left ear, thus causing the above symptoms, and in severe cases, there will be pain. 3. Insufficient blood supply to the brain: Insufficient blood supply to the brain can cause nerve dysfunction in the corresponding innervated area, thus causing the symptom of numbness in the left ear. If you have symptoms of long-term numbness of the ear, it is recommended that you go to the hospital in time to clarify the cause and get reasonable treatment.