Induction of atopic dermatitis by epicutaneous sensitisation with Dermatophagoides farinae in nongenetically predisposed Beagle dogs

This study was performed to induce atopic dermatitis (AD) using nongenetically predisposed Beagle dogs. Five healthy Beagle dogs were used. Twice weekly for 12 weeks, the dogs were painted on the axillae and groin with a solution of Dermatophagoides farinae (D. farinae). Each dog was thereafter placed in a cage where a house dust mite (HDM) solution was applied on the bottom of the cage. The dog remained in the cage for 3 h daily for 3 consecutive days for the environmental exposure to HDM. Serum samples were collected at 0 week and 6 weeks after sensitisation, and at 0 h and 72 h after the environmental exposure. During the environmental exposure, skin biopsies were obtained at 0 h, 36 h, and 72 hours. After the first environmental exposure, no dog had any marked clinical sign. An additional sensitisation was subsequently administered for 10-13 weeks. Three of the five dogs developed pruritic dermatitis with skin lesions after the second exposure. The histopathology of the lesions revealed severe infiltration of inflammatory cells and dermal oedema. The levels of D. farinae-specific IgE were also elevated. This study demonstrated that AD could be induced by epicutaneous sensitisation with HDM in nongenetically predisposed dogs.