Hannah Zulueta The Itchy Dog Work-Up
Canine atopic dermatitis has no single confirming test. In conventional veterinary dermatology it is a diagnosis of exclusion. You rule out the look-alikes, match the clinical picture, then allergy-test only to choose allergens for immunotherapy. The read is in the map: where the itch lands narrows the field before any test is run.
Rule out the look-alikes
Fleas, mites, bacterial and yeast infection, and food. Flea comb, scrape, cytology, and a strict diet trial. This is the work-up.
Match the clinical picture
Distribution, history, and Favrot’s criteria. Applies only to itchy dogs and yields suspicion, not a diagnosis.
Allergy-test to pick allergens
Intradermal or IgE serology, after the diagnosis is made. It identifies targets for immunotherapy. It does not diagnose the disease.
The differential at a glance
| Condition | Category | Where the itch lands | How it is ruled in | The tell |
|---|
Favrot’s criteria
A clinical checklist for an already-itchy dog, once the work-up is done.
- 1Onset of signs before 3 years of age
- 2Dog lives mostly indoors
- 3Itch responds to corticosteroids
- 4Itch without lesions at onset (alesional)
- 5Front feet affected
- 6Ear pinnae affected
- 7Ear margins not affected
- 8Dorsolumbar area not affected
The elimination diet trial
The one rule-out that lives in the nutrition lane.
- Strict and exclusive for a minimum of 8 weeks, then rechallenge with the old diet to confirm.
- A novel protein the dog has never eaten (rabbit, kangaroo, venison, horse) or a hydrolyzed protein.
- A properly built home-cooked diet is the most controllable option.
- Common offenders: beef, dairy, chicken, wheat, then soy, lamb, pork, fish, corn.
- Watch the leaks: flavored medications, chews, table scraps, another pet’s bowl, even crumbs.
Important note: a vet does not call an itch an allergy until fleas, mites, infection, and food have been ruled out and the signs still fit. The allergy test comes last, and it shows which allergens are involved, not whether allergies are the cause. This tool is here to help you learn. It walks you through how the work-up is done so you can understand each step, ask good questions, and give informed consent for your dog’s care. Diagnosis and treatment stay with your vet.
Source: Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. Favrot et al. Vet Dermatol. 2010;21:23-31.
Hannah Zulueta obtained her Certificate in Canine Nutrition from CASI Institute. She is also studying for her Doctorate in Acupuncture, Traditional Chinese Medicine, and Herbalism from the esteemed Pacific College of Health and Medicine. If you’re as keenly interested in health for yourself, visit her website for human health: Satori Acupuncture and Herbs.
She resides in San Diego with her three dogs, Maggie, Orbit, and Mr. Higgins.
She is available for one on one consultations. She develops evidence-based recipes that meet both NRC and AAFCO nutritional standards while integrating the therapeutic food principles of Traditional Chinese Veterinary Medicine into her formulations.
Additionally, you can find her sharing free content on Instagram.
