Numbness of the left scalp may be a sign of neurodermatitis, cervical spine disease, vegetative nerve disorder, cerebrovascular disease and other diseases. 1. Neurodermatitis: such as herpes virus-induced neurodermatitis, in addition to skin damage, burning pain and other symptoms, it will also cause numbness of the scalp. At this time, you should go to the dermatology department of the hospital in a timely manner in order to clarify the cause of the disease and treatment. 2. Cervical spine disease: such as cervical disc herniation, cervical spondylosis, etc., may lead to cervical vertebrae displacement, so that the peripheral blood vessels are compressed, blood circulation is impeded, and then appear into the scalp numbness, pain and other symptoms. 3. Vegetative nerve disorders: mainly due to long-term mental tension, emotional depression, resulting in brain fatigue, so that the brain neurons are damaged, the left side of the scalp numbness symptoms. 4. Cerebrovascular diseases: such as arteriosclerosis, cerebral hemorrhage, cerebral infarction, hypertension, etc., can make the blood circulation in the brain is impaired, so that the sensory abnormalities, which can be manifested as numbness of the scalp and other symptoms. When the left scalp is numb, promote blood circulation in the scalp by combing and massaging to relieve the symptoms of scalp numbness. If the symptoms continue to be unrelieved, it is recommended to go to the hospital for examination to clarify the cause of the disease and treatment under the guidance of a professional physician.