Perennial cold lower limbs according to the symptoms and signs to choose the appropriate examination, such as blood routine, erythrocyte sedimentation rate, C-reactive protein measurement, X-ray examination, ultrasound, arteriography, nail function and so on. Firstly, the doctor will ask about the medical history, and then carry out common specialized tests such as walking test, elevation and sagging test of the affected limb, capillary filling time, excitation test, etc., and then choose the appropriate tests and laboratory tests to further clarify the cause of the disease according to the preliminary judgment. Cold lower extremities can be seen in peripheral neuropathy, lower extremity arteriosclerosis, thromboembolic vasculitis, rheumatism, rheumatoid rheumatism, hypothyroidism and so on. According to the condition of the patient, the doctor will use blood test, erythrocyte sedimentation rate, C-reactive protein measurement, X-ray examination, ultrasound, arteriography, thyroid function and other tests. Seek medical treatment in time and under doctor’s guidance, do not use medication without authorization.