Feline asthma encompasses such pathologies as chronic bronchitis, allergic bronchitis, bronchial asthma and chronic allergic bronchitis, affecting 3-5% of the feline population. It presents as a result of abnormal hypersensitivity responses to environmental irritants1. It is characterised by a reduction to the bronchial lumen caused by acute bronchoconstriction, oedema and an increase in airway mucous secretion2.
The interaction between eosinophils and T helper lymphocytes (Th2) when responding to inflammatory stimuli leads to the production of IgE for the antigen inhaled, causing the degranulation of mast cells and eosinophils. This releases vasoactive and inflammatory substances that cause an irritative response in the respiratory epithelium, leading to hypertrophy, metaplasia, erosion and epithelial ulceration.
An increase in certain interleukins, such as IL-4, IL-5, IL-6 and others3, has also been observed in this process. This causes mucous secretion and leads to smooth muscle contraction.
