Allergen-specific immunotherapy (ASIT) is the only known mechanism for altering the disease process of canine atopic dermatitis. It modulates the disease by inducing a shift of the T-cell response from a T helper 2 to a T helper 1 response. In veterinary medicine, ASIT is administered via subcutaneous injections; however, there is increasing interest in adapting oral immunotherapy as an alternative treatment option. In this study, 2 groups of house dust mite atopic beagle dogs were divided into a placebo group and a treatment group. The treatment group received oral house dust mite allergen mixed in cream cheese once daily for 7 days and the placebo group received only cream cheese. Dogs were evaluated for clinical signs using a modified Canine Atopic Dermatitis Extent and Severity Index (CADESI) prior to, 2 months after, and 7 months after the start of treatment. Oral therapy was well tolerated by the treatment group without adverse effects; however, comparison of CADESI scores and allergen-specific IgE levels showed no difference between the treatment and placebo groups.
Commentary: The method of oral allergen administration may be important in the immune response. In this study, the investigators found no significant benefit when the allergen was administered orally to dogs in cream cheese. Method of delivery may be an issue, as dogs ingested the allergen in this study rather than having it contact the oral mucosa. In 2007, a pilot study using sublingual immunotherapy (SLIT) showed significant benefit in 8 of 10 dogs with naturally occurring house dust mite allergy.1 In addition, IgE levels to house dust mite decreased while IgG levels to house dust mite increased. Since that time, SLIT (allergy drops) has become a standard option for clients electing ASIT at that institution. The only adverse effects noted were occasional episodes of facial itching after administration. SLIT therapy is administered twice daily; there is no decrease in the interval between treatments as with allergen injections. SLIT is a viable option for clients and will become more widely available.—Karen A. Moriello, DVM, Diplomate ACVD
Tolerability and clinical efficacy of oral immunotherapy with house dust mites in a model of canine atopic dermatitis: A pilot study. Marsella R. VET DERMATOL 21:566-571, 2010.
1. Changes in mite specific IgE and IgG levels during sublingual immunotherapy (SLIT) in dust mite sensitive dogs with atopic dermatitis. DeBoer DJ, Verbrugge M, Morris M. Vet Dermatol 21:531 (abstract), 2010.