Itchy Dog: Causes and Treatment Do you have a dog who’s constantly scratching? noida pet clinic tell that itchy dog is one of the most difficult problems to assess in veterinary medicine. It is often hard to find the underlying cause and even when found, it often involves lifelong therapy for the dog. Today, the most common cause of itchiness is allergies. But the challenge is this: What is your dog allergic to? And, once that substance has been identified, what is the best way to treat her? The following are the steps that NOIDA PET CLINIC vets recommend. The order is variable, based on the signs the dog might be showing and what has or has not worked. Some standard diagnostic tests can be done. A CBC (complete blood count) and chemistry profile can detect systemic disease and infections.