A retrospective, multicentric controlled study of the effect of specific allergen immunotherapy on medication needs in cats with atopic skin syndrome

BACKGROUND: Intradermal allergen testing (IDT) and allergen-specific immunotherapy (ASIT) remain underrated in feline dermatology. HYPOTHESIS/OBJECTIVES: The objectives of this retrospective study were to report the results of IDT and the effects of ASIT on the medication needs in a population of 158 cats diagnosed with feline atopic skin syndrome (FASS). MATERIALS AND METHODS: FASS was diagnosed after the exclusion of other pruritic conditions. IDT was performed under sedation/anaesthesia in 158 cats; in 136 of them, intravenous fluorescein and a Wood's lamp were used to facilitate interpretation. The medication scores were compared between cats with and without ASIT over a 1-year follow-up period. RESULTS: IDT was interpretable in 153 cats (97%) of which no specific sensitisation could be detected in 53 cases (35%). Among the remaining 100 (65%) cats, polysensitisation and monosensitisation were observed in 78 and 22 cases, respectively. Cats were sensitised to house dust mites (HDM; 74%) including Dermatophagoides farinae (67%) and D. pteronyssinus (27%); storage mites (SM; 44%) including Tyrophagus putrescentiae (27%), Acarus siro (32%) and Lepidoglyphus destructor (8%); moulds (7%); grasses (18%); weeds (19%); tree pollens (19%); and fleas (17%). ASIT was initiated in 78 of 100 cats, and a 1-year follow-up period was available for 42. ASIT had no effect in 11 cats (26%). In the remaining 31 cats (74%), ASIT was associated with a significant reduction (≥ 30%) in medication scores. CONCLUSIONS AND CLINICAL RELEVANCE: ASIT is associated with a sparing effect in a significantly greater number of treated cats than untreated ones.