Numbness of the skin on the outside of the thigh may be caused by nerve damage or paralysis, common diseases such as herpes zoster, diabetes, peripheral neuritis, trauma and so on. 1. Herpes zoster: a skin disease caused by varicella zoster virus in the body, the virus infection may cause nerve edema, resulting in symptoms of numbness of the outer thigh skin. 2. Diabetes mellitus: diabetes mellitus is a chronic metabolic disease, and patients with a long history of the disease may develop diabetic peripheral neuropathy, which causes abnormalities in the local sensory nerves and leads to numbness of the skin on the outside of the thighs. 3. Peripheral neuritis: Inflammatory reaction of peripheral nerves caused by various reasons will result in abnormal sensation of the limbs, which may lead to numbness of the skin of the outer thigh. 4. Trauma: trauma to the outer thigh may damage the local sensory nerves, resulting in numbness of the outer thigh skin. Numbness of the skin on the outer thigh may also be caused by other reasons, it is recommended that patients go to the hospital in time for examination, clear diagnosis and treatment as prescribed by the doctor.