My friends dog suffers from skin problems, abit like a dog skin exma and he itches it alot. I suggested she tried giving him the Yeomega oil on a daily basis and it actually cleared it up and the dog has since stopped itching.
Yeomega is available online or at Pets At Home, a bottle costs around £10 and will last you for approx a month. It also helps prevent alot of hair loss, I give it to my two JRs. Might be worth a try to see if it helps?