I have a Westie who has a similar problem, my vet recommended giving her evening primrose oil (just the hums gelatin capsules) and this seems to reduce it considerably. She still does it occassionally but not half as much as she used to.
We also use Bob Marten's hypoallergenic dog shampoo which is less likeley to irritate her skin
Sounds like he/she might be having an allergic reaction to a flea bite. My dog had the same thing. Take him along to the vets and you'll get some cream and maybe an injection depending on how bad it is. Unfortunately once they've had an allergic reaction it'll always happen if he's ever bitten by one of the little bleeders.
i have a small bitch she all ways scrathing and look in aloy of discomfort.plz is there a cream that i can get? i am in ******* so tell me something that i can get here.