Late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with house dust mite-induced atopic dermatitis.
OBJECTIVE
To determine the prevalence of late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with atopic dermatitis and an immediate reaction to D farinae.


METHODS
6 healthy dogs and 20 dogs with atopic dermatitis and immediate reactions to D farinae.


METHODS
ntradermal tests were performed with D farinae at 1:1,000 wt/vol and 1:50,000 wt/vol concentrations, and skin reactivity was evaluated after 0.25, 6, and 24 hours. Serum D farinae-specific IgE antibodies were assayed. Extent of lesions (atopy index) and pruritus (visual analogue scale) were evaluated in dogs with atopic dermatitis.


RESULTS
Late-phase reactions were observed in healthy dogs at 6 hours (n = 2 dogs) and 24 hours (1) with the 1:1,000 wt/vol concentration, and at 6 hours (1) and 24 hours (1) with the 1:50,000 wt/vol concentration of allergen. Late-phase reactions in healthy dogs were only observed in dogs with an immediate reaction to D farinae. Late-phase reactions were observed in 11 of 20 dogs with atopic dermatitis at 6 and 24 hours with the 1:1,000 wt/vol concentration and in 10 of 20 at 6 and 24 hours with the 1:50,000 wt/vol concentration of allergen. There was no difference in mean atopy index, mean visual analogue scale of pruritus, or mean serum D farinae-specific IgE concentration of dogs with a late-phase reaction, compared to dogs without a late-phase reaction.


CONCLUSIONS
Late-phase reactions may be observed after an immediate reaction to intradermal skin testing in healthy and allergic dogs but are more commonly observed in dogs with atopic dermatitis.
Hillier
Andrew
A
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Cole
Lynette K
LK
Kwochka
Kenneth W
KW
McCall
Catherine
C
D000485:Allergens / Q000008:administration & dosage; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000008:administration & dosage*; D003876:Dermatitis, Atopic / Q000276:immunology / Q000662:veterinary*; D004283:Dog Diseases / Q000276:immunology*; D004285:Dogs; D004306:Dose-Response Relationship, Immunologic; D005188:False Negative Reactions; D006968:Hypersensitivity, Delayed / Q000662:veterinary*; D006969:Hypersensitivity, Immediate / Q000662:veterinary; D007073:Immunoglobulin E / Q000097:blood; D007428:Intradermal Tests / Q000662:veterinary*
D000485:Allergens; D039741:Antigens, Dermatophagoides; D007073:Immunoglobulin E