Extremely itchy rash that spreads and appears contagious, kindly suggest remedies

Hi, My two grandsons aged 5 and 6 developed a severly itchy rash on their stomach area about 18 months ago. The doctors told them to use a cortizone cream and calamine lotion to relieve the itch and not scratch. Well after about 4 monthss the rach cleared up on the 6 year old. However the 5 year old s has continued to spread upwards and around to his back. His stomach literally looks like stucco he has so many pimple like bumps. He has been to several specialists and all they have come up with is that it is viral, and related to chicken pox and must run its course. This child is miserable and embarassed by how awful it looks, and it is now spreading to his neck and up his chin. One dermatologist wanted to treat him with steroids but his primary overruled him. I have tried every topical cream I can find, and the only one that gives him any relief is lanacaine with aloe. Please help!! PS : now his best friend has come down with it too, so it seems to be contagious .