Comparing Atopic Dermatitis & Atopic-Like Dermatitis in Dogs

In the Literature

Botoni LS, Torres SMF, Koch SN, Heinemann MB, Costa-Val AP. Comparison of demographic data, disease severity and response to treatment, between dogs with atopic dermatitis and atopic-like dermatitis: a retrospective study. Vet Dermatol. 2019;30(1):10-e4.

The Research …

In dogs, atopic dermatitis (AD) is an inflammatory and pruritic skin disease associated with immunoglobulin E and is most commonly directed against environmental substances. Atopic-like dermatitis (ALD) often has the same clinical presentation as AD, but an immunoglobulin E component cannot be demonstrated. Immunoglobulin E serum levels are poorly correlated with canine AD; thus, AD and ALD are differentiated based on results of intradermal and serum allergen-specific testing.

This study compared 216 dogs that had AD and 37 dogs that had ALD. Dogs were enrolled in the ALD group if both allergen-specific and intradermal test results were negative. Dogs were enrolled in the AD group if at least one of these tests was positive. Investigators compared maintenance therapy protocols, pruritus levels, number of body sites affected before and after therapy, and demographic data. Although certain breeds (ie, Labrador retrievers, English bulldogs, American Staffordshire terriers, soft-coated wheaten terriers) were overrepresented in the AD group, there was otherwise no significant difference between the AD and ALD groups. Both groups had similar findings, with similar age of onset, similar pruritus levels, and  similar response to treatment.

… The Takeaways

Key pearls to put into practice:

• The finding of no significant differences between dogs that had AD and dogs that had ALD suggests that both conditions are manifestations of the same disease process. Further study is needed to support this.

• Allergy testing is recommended in dogs that have clinical signs compatible with AD. If positive allergy test results can be demonstrated, immunotherapy is advised, as this is the only treatment that can reverse or potentially cure a dog that has an allergy, rather than just mask the clinical signs.

• Allergen-specific immunotherapy should not be initiated if allergy testing fails to document any hypersensitivities. In such cases, the clinician should use therapies judiciously to decrease clinical signs and maintain comfort.

• Allergen-specific and intradermal testing test for allergy differently. If a patient is negative on allergen-specific testing, intradermal testing may still yield a positive result; thus, it is recommended these cases be referred to a board-certified veterinary dermatologist for intradermal testing.