Patients with cold thighs should consider two conditions, as follows: First, vascular origin causes: the presence of vascular diseases of the lower limbs, such as lower limb occlusive vasculitis, there is often occlusion of the veins and arteries, and the blood supply to the lower limbs is reduced, so that there will be coldness in the lower limbs, and there will also be intermittent claudication and cold pain in the lower limbs. In this case, you must go for early vascular ultrasound examination of the lower limbs to clarify whether there is a vascular disease. Second, neurogenic causes: generally due to compression of the sciatic or spinal nerve, when the nerve is compressed, it can cause radiating pain and numbness in the lower limbs. However, some patients can show abnormal sensation in the lower extremities, which can be manifested as localized coldness, which can only be clarified by MRI and CT examination of the lumbar spine.