The main causes of numbness in the thighs after blowing wind are considered to be related to lesions in the blood vessels of the lower limbs, lesions in the lumbar vertebrae and anemia. 1. Lower extremity vascular lesions: if vasculitis, varicose veins, etc. occur in the thigh area, it is easy to affect the local blood circulation, which will cause numbness after blowing wind. 2. Lumbar spine lesions: when there are lumbar spine lesions, such as lumbar intervertebral disc herniation or lumbar spinal stenosis and other structural changes, it is easy to compress the nerve root to affect the motor and sensory functions of the lower limbs, which will lead to the symptoms of numbness of the thighs after blowing wind. 3. Anemia: for patients with anemia, it is easy to appear the phenomenon of poor blood circulation in the limbs, in contact with cold stimuli easily triggered numbness in the limbs, so the symptoms of numbness in the thighs after blowing the wind. Usually pay attention to keep warm, do not blow cold wind for a long time, so as not to aggravate the symptoms. If the symptoms persist for a long time, you need to consult a doctor for examination and standardized treatment under the guidance of a professional doctor.