Background: Atopic dermatitis (AD) is one of the most common skin diseases in small animal practice. Allergen immunotherapy (AIT) is the only curative treatment for the disease, and oral, subcutaneous and intralymphatic administration of allergens are commonly employed. Objectives: To compare the efficacy of AIT following an induction phase with intralymphatic injections (ILIT) or rush immunotherapy (RIT). Animals: Fifty privately owned dogs with AD. Materials and Methods:In a double-blinded study, dogs were randomly assigned to either four monthly ILIT of allergen extract or RIT with five injections administered subcutaneously at hourly intervals on the first day. They were assessed by validated scores; Canine Atopic Dermatitis Lesion Index (CADLI) and pruritus Visual Analog Scale (PVAS) at the beginning of the study and after 1, 3, 6 and 12 months. The latter were performed daily for 7 days before each revisit. Medication scores and a total clinical score were calculated and compared between each group and time point. Results: There was no significant difference in CADLI and PVAS scores, or CADLI and medication scores between groups at any of the time points. A significant improvement with both ILIT and RIT was seen in total and pruritus scores, respectively. An owner global assessment of good-to-excellent treatment efficacy was seen in 40% of the dogs; total scores improved by 27% and 35% in the RIT and ILIT group, respectively. Adverse effects were not seen. Conclusions and Clinical Relevance: Induction of AIT can be conducted either as RIT or ILIT with no loss in efficacy.

BackgroundThe duration of the induction phase of allergen‐specific immunotherapy conventionally is a period of several weeks, during which the volume of an allergen solution, administered by injection, is gradually increased until the maintenance dose is reached. In rush immunotherapy (RIT), the induction period is abbreviated to achieve a faster improvement in clinical signs of atopic dermatitis (AD) compared to conventional immunotherapy.ObjectiveThe aim of this retrospective study was to evaluate the safety of RIT in 230 dogs with AD and report any adverse effects (AE).AnimalsTwo hundred thirty client‐owned dogs.Materials and MethodsMedical records of dogs receiving RIT between 2012 and 2021 were analysed and observed AE were investigated. All dogs underwent RIT following a protocol of subcutaneous allergen extract injections, given hourly with an incrementally increasing volume from 0.1 to 1.0 mL.ResultsAdverse effects were documented in 6 of 230 (2.6%) dogs. Five of these dogs (2.2%) showed mild gastrointestinal signs (1 of 5 vomiting, 4 of 5 diarrhoea) and one patient an increase in body temperature by 1.5°C. These occurred at different stages of the RIT protocol. All AE were graded as mild and self‐limiting.Conclusions and Clinical RelevanceBased on these data, supervised RIT in dogs appears to be a safe procedure to achieve the maintenance dose of allergen immunotherapy earlier with infrequent and mild AE.