In this video, hosted by Ana Isabel and her dog Teddy on Youtube, Pete discusses the reasons why dogs can become itchy, outlining the process that vets use to make a diagnosis, and then to provide effective treatment.
If you cannot see the video in this post, you can watch it here.
Please note that I am unable to answer veterinary questions in comments. If you have questions or concerns about your pet's health it is always better to contact your vet.