Why Does My Dog or Cat Scratch So Much?

This very common client question unfortunately often has a complex answer, depending upon the individual pet. The first lesson in veterinary dermatology that we learned in veterinary school is to do a skin scraping, looking for scabies or demodex mange mites (more commonly seen in dogs), as well as taking scrapings for overgrowth of yeast or fungi like ringworm.

If these tests are negative the most common cause of scratching is often termed “allergies.” The three broadest causes of these allergies in dogs and cats, include flea bite allergies, inhalant/contact allergies to molds, grasses, trees, dander, house dust mites, pollens, and food allergies.  Some pets can have multiple factors from these three major groups. These frustrating itchy dogs and itchy cats can often develop secondary bacterial or yeast infections, which must also be addressed if the scratching is to be resolved. Often secondary oral antibiotics or antifungal medications are needed, which can be determined by a veterinary exam and the above testing. In middle aged and older pets, we will sometimes see hormonal disorders as contributing to skin infections and itchy pets.  So, sometimes thyroid and adrenal gland function testing are indicated depending upon the individual pet’s presentation.

Is your cat constantly scratching? One of the first things a veterinarian may do for a very itchy dog is to sometimes treat for hidden scabies mites (which do not often show up on skin scrape) with products like Ivermectin or Revolution, as well as change a pet to a low allergy, novel protein prescription diet for a minimum of a few months. In addition, a veterinarian may treat the secondary bacterial or yeast infections from all of the itching with appropriate antimicrobials and specific shampoos, such as Ketochlor, Oxydex, or Chlorhexidine Shampoo; especially in pets with secondary infections contributing to the scratching. For cats, a low allergy diet is often tried as well.

If there is not adequate improvement in the itching, then veterinary dermatologists will often perform blood and/or skin allergy testing to find out what a pet is allergic to, so that appropriate allergy treatment can be formulated. If a client goes through an entire dermatology workup, costs can climb quickly, especially with the allergy testing and recheck exams, as often up to one year of allergy vaccines are tried before deeming treatment a success or failure.  Average success rates for inhalant/contact allergy dogs and cats (also known as atopic dogs/cats) can range from 60 to 70 percent. For the remainder of the patients, and for those animal guardians who do not go for a complete dermatology workup, symptomatic management with various antihistamines like Diphenhydramine, Chlorpheniramine, and Clemastine can be tried.  When combined with excellent Omega 3 fatty acids like Be Well, Super Omega 3, or Missing Link for Dogs and Missing Link for Cats, and appropriate shampoo therapy, symptoms can often be controlled, but are difficult to cure.

Prescription  allergy pet meds like Atopica and Prednisone are needed for extremely itchy, nonresponding pets. Natural supplements like Proanthozone, DMG liquid, or Yucca Intensive may also offer effective alternatives in itchy pets.  I find that no one protocol works best in all pets, and that various combinations from the above groups and various therapeutic trials are needed to find the right combination that works best in a given pet. In addition, all itchy pets should be on some sort of flea preventative product, whether conventional Advantage or Frontline Plus, or natural flea and tick products to eliminate the always potential possibility of flea bite allergies involved.

Related Posts


  1. I want to add Omega 3 oil to my dog’s diet. Is what I take, otc fish oil, ok for my dog?

  2. Dr. Michael Dym, VMD veterinarianJanuary 25, 2015 at 3:53 pm

    That is fine, but I usually like the pet approved products and doses such as nordic naturals pet omega 3 from 1800petmeds.

Leave a Comment