Update on Allergen Immunotherapy.

Allergen immunotherapy has been used for many years in dogs and cats and is the only specific treatment of atopic dermatitis that changes the patho-mechanisms of disease by stimulating allergen tolerance. Subcutaneous administration of allergens is the most commonly used administration route, typically in increasing concentrations (induction period) followed by long-term injection of allergen extract (maintenance therapy). Rush protocols with an abbreviated induction period have been reported and shown to be safe in dogs. More recently, oro-mucosal and intralymphatic administration of allergens has been evaluated in dogs. Approximately two-thirds of patients show good to excellent improvement of clinical signs.