Insect Bite Hypersensitivity in Horses is Associated with Airway Hyperreactivity. (18th September 2017)

• Record Type: Journal Article
• Authors: Lanz, S.; Brunner, A.; Graubner, C.; Marti, E.; Gerber, V.
• Is Part Of: Journal of veterinary internal medicine. Volume 31:Number 6(2017)
• Page Start: 1877
• Page End: 1883
• Publication Date: 2017-09-18
• Subjects: Equine asthma -- Horse -- Insect bite hypersensitivity -- Multiple equine allergies; Veterinary medicine -- Periodicals; 636.0896
• DOI: 10.1111/jvim.14817
• Languages: English
• ISSNs: 0891-6640

Abstract

Abstract : Background: Genetic and epidemiologic evidence suggests that in horses, as in other species, different manifestations of hypersensitivity may occur together. Hypothesis: Horses affected with insect bite hypersensitivity (IBH) show airway hyperreactivity (AH) to inhaled histamine, even in the absence of overt clinical signs of equine asthma (EA). Animals: Twenty‐two healthy controls (group C), 24 horses suffering from IBH alone (group IBH), and 23 horses suffering from IBH and EA (group IBH/EA). Methods: The clinical histories were assessed using 2 standardized questionnaires, the Horse Owner Assessed Respiratory Signs Index (HOARSI), and IBH scoring. Horses were classified as EA‐affected if their HOARSI was >1 and as IBH‐affected if IBH score was >0. Confounding disorders were excluded by clinical examination. The arterial partial pressure of oxygen (PaO2 ) was measured and flowmetric plethysmography used to assess airway reactivity to increasing doses of inhaled histamine. Results: The median histamine provocation concentration (PC) when ∆flow values increased by 35% (PC35) was significantly higher in group C (5.94 [1.11–26.33] mg/mL) compared to group IBH (2.95 [0.23–10.13] mg/mL) and group IBH/EA (2.03 [0.43–10.94] mg/mL; P < 0.01). The PC50 and PC75 showed very similar differences between groups. Furthermore, PaO2 was significantly lower in group IBH (84 ± 8 mmHg) and group IBH/EA (78 ± 11 mmHg) compared to group C (89 ± 6 mmHg; P < 0.01). Conclusions and Clinical Importance: IBH is associated with AH and decreased PaO2, even in the absence of overt respiratory clinical signs.