What Causes Itchy Bumps On The Skin?

my son is nearly 8 years old and has had a rash which starts off as skin coloured bumps which are extremely itchy and now look like clusters of pinprick scabs. My doctor is referring us to a skin specialist however in the meantime I'd like some information on how to deal with them. Originally he thought it was a case of scabies and is now considering dermatitis herpetiformis. I had my son tested for a gluten intolereance the results indicated he was fine. Any advice would be much appreciated.