The causes of itchy skin on the lower legs are blood spots when you scratch, including neurodermatitis, eczema, chicken pox, scabies and so on. 1. Neurodermatitis: neurodermatitis will appear paroxysmal symptoms of intense itching, mild scratching is not effective, so a scratch are blood spots. 2. Eczema: eczema patients will generally have intense itching of the calves, so there will be a scratch are blood spots phenomenon. 3. Chickenpox: Due to chickenpox-herpes zoster virus infection, these viruses can damage the skin, so the symptoms of scratching are blood spots. 4. Scabies: Scabies patients generally very serious itching, and scabies can damage the skin, so the phenomenon of blood spots. Calf skin itching a scratch are blood spots may have other reasons, it is recommended that timely medical care, clear cause of the symptomatic treatment, do not blindly deal with.