I have spent the last two weeks on our dermatology service and it was one of my favorite rotations so far (it helps when your clinicians, technicians, and rotations mates are awesome!). In our third-year dermatology unit, one piece of information always stuck with me. Out of the top 10 reasons that dogs are brought to the vet, four of those are dermatology related and three are the top reasons (#1 ear infections, #2 skin allergies, and #3 pyoderma/hot spots). I knew early on then that dermatology is important to understand and I made sure to have the elective on my clinical year schedule.
One common compliant patients had was pruritus, or itching. Many patients were referred to the service because they were not getting better. I was always surprised at how many patients came to us never having had any real diagnostic tests done. A dermatology database is an important tool in your toolbox when evaluating an itchy patient. These include:
- Impression smear
- Trichogram
- Skin scraping
- Ear cytology or cytology of skin lesions
Depending on what clinical signs and patterns of lesions are present, you can pick different diagnostic tests based on your clinical suspicion or rule out diseases. For example, a dog that is extremely itchy and has crusts on the ear margin, you may want to perform skin scraping, impression smears, and ear cytology to rule out a Scabies infestation. Allergies were one of the most frustrating diseases to diagnose and treat. Remember there are two big categories including environmental and food allergies. One big thing I took away from my dermatology rotation is that there is NO BLOOD OR SKIN TEST FOR FOOD ALLERGIES! Blood tests, even though companies offer them, are not validated for food. The only true way to diagnose a food allergy is with a strict food trial that can last anywhere from 8-12 weeks depending on your preference.
So the next time you have an itchy dog, remember to use your diagnostic toolbox (and don’t just throw an antibiotic band-aid on it unless there is a diagnosed infection).
