Determination of threshold concentrations of plant pollens in intradermal testing using fluorescein in clinically healthy nonallergic cats.

BACKGROUND: Currently the same allergen concentrations for canine intradermal testing (IDT) are recommended for feline IDT. Feline skin reactions are subtle and more difficult to read than canine reactions. This difference may be due to suboptimal allergen concentrations used for IDT in cats. HYPOTHESIS/OBJECTIVES: To determine the irritant threshold concentration (ITC) of 16 pollen allergens using serial dilutions of allergen and intravenous fluorescein. The hypothesis tested was that feline IDT currently is performed at suboptimal allergen concentrations for pollens. ANIMALS: Twenty privately owned healthy clinically nonallergic cats. METHODS: IDT was performed in duplicate using 16 pollen allergens (weeds, grasses and trees) at a dilution of 8000 PNU/mL. Two blinded investigators graded the test reactions independently using subjective and objective criteria. Intravenous fluorescein was then administered and the test reactions were re-evaluated. IDT was repeated for any allergen that was positive, using serial dilutions of allergen at a concentration of 6000 and 4000 PNU/mL. RESULTS: The ITC for 2 of 16 of the allergens was determined. The ITC of Cynodon dactylon (Bermuda grass) and Schinus spp. (Peppercorn) was determined to be between 6000 and 8000 PNU/mL. The ITC of all other allergens tested in this study was >8000 PNU/mL. CONCLUSIONS AND CLINICAL IMPORTANCE: This study confirms that suboptimal allergen concentrations currently are used for feline IDT as the ITC is >8000 PNU/mL for 14 of 16 of the grass, weed and tree pollens evaluated. The ITC of Cynodon dactylon and Schinus spp. was determined to be between 6000 and 8000 PNU/mL.

First report of angio-oedema subsequent to the administration of allergen specific sublingual immunotherapy for the management of equine hypersensitivity dermatitis.

BACKGROUND: Sublingual immunotherapy (SLIT) offers an alternative mode of allergen delivery to subcutaneous immunotherapy (SCIT) with the aim of inducing immunological tolerance. Currently, there are no published reports regarding the efficacy or safety of SLIT in horses. HYPOTHESIS/OBJECTIVE: To describe the first case of several adverse events occurring in a horse subsequent to the repeat administration of SLIT. ANIMAL: A seven-year-old, warmblood mare with a confirmed diagnosis of equine hypersensitivity dermatitis (EHD). METHODS AND RESULTS: Immunotherapy was recommended for management of EHD. Due to the temperament of the horse, the owner elected to proceed with SLIT. Thirty six hours after commencing SLIT, the mare developed scleral oedema, moderate dyspnoea and abdominal discomfort. SLIT was withdrawn for 10 days and re instituted using a ten-fold dilution of the original vaccine. Localized oedema and swelling of the tongue developed within 12 h of administration. At this juncture, SLIT was withdrawn. The horse was rechallenged with the SLIT allergen vehicle, 50% glycerine and no adverse reactions occurred. SCIT was commenced using the same allergens and no adverse events occurred with repeated administration. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first reported case of adverse reactions developing subsequent to the administration of SLIT for the management of EHD.

Focal metatarsal fistulae syndrome affecting a greyhound dog successfully treated with topical 0.1% tacrolimus ointment.

Metatarsal fistulation is an uncommon cutaneous condition reported almost exclusively in German shepherd dogs and their cross-breeds. To the best of the authors' knowledge this is the first reported case of focal metatarsal fistulae syndrome affecting a greyhound. Remission was obtained within 6 weeks of commencing treatment using compounded 0.1% tacrolimus ointment twice daily and the dog remained stable for another 6 months with twice weekly application before treatment was discontinued. The dog remained in remission at the time of writing, which is 1 year after treatment withdrawal.