Suggest Remedy For Itchy Skin Infections In Children

Hello my six year old son has itchy skin. He will scratch until it bleeds. The doctor took a quick look and just said it is most likely dry skin. I now double rinse all the laundry and slather him in vaseline. He is still itchy. He has had this for a long time but it is not always so bad. A few times now I caught him before he scratched too much and I noticed that where he was scratching there was a bump. It is not discoloured just raised skin bump that is extremely itchy. He has it mainly on his ankles, arms and now one on his face and his tummy.
Please let me know your advice.