The common causes of a hot flow in the back of the thigh include change in posture, sciatica, local infection, peripheral neuropathy, etc. 1. Posture change: prolonged compression of the back of the thighs, easy to cause local blood circulation is not good, when the position changes, blood circulation is smooth, there may be a feeling of heat flow in the back of the thighs. 2. Sciatica: If the sciatic nerve is compressed due to lumbar disc herniation or lumbar spinal stenosis, sciatic nerve pain may easily occur, and sensory abnormalities may also occur. 3. Localized infection: if the patient’s posterior thigh is infected, such as bacterial infection, cellulitis, etc., it is easy to have the feeling of a hot stream on the posterior thigh, and local redness and swelling may also occur. 4. Peripheral neuropathy: If the blood sugar level of diabetic patients is poorly controlled for a long time, it is easy to induce diabetic peripheral neuropathy, and local sensory abnormalities will occur. Causes of a hot stream on the back of the thigh are more reasons, if the symptoms continue without relief, it is recommended to go to the hospital in time to identify the cause of the disease, under the guidance of the doctor for targeted treatment.