How do you diagnose atopic dermatitis in a dog? That’s right. Based upon clinical features. Serum IgE and intradermal testing can be used to identify potential allergens, but the tests are not sensitive or specific enough to rely upon for making the diagnosis. Luckily, in 2010, Claude Favrot and colleagues published a nice paper on the clinical features of canine atopic dermatitis (Veterinary Dermatology 2010; 21: 23-31). In the appendix, there is a very useful checklist that you can use to make a diagnosis. There are various versions of it, but this one is 85% sensitive and 79% specific when dogs meet five out of eight of these criteria:
- Age at onset < 3 years
- Mostly indoor
- Corticosteroid-responsive pruritus
- Chronic or recurrent yeast infections
- Affected front feet
- Affected ear pinnae
- Non-affected ear margins
- Non-affected dorso-lumbar area
You’ll still want to rule out any other differentials that are suggested by the findings:
- Food allergy
- Sarcoptes
- Flea allergy
- Demodicosis
Next week’s post will be on interpreting fungal cultures.
Jon Plant, DVM, DACVD
SkinVet 