Update on equine ‘asthma’

A recent development in relation to equine pulmonology is change in nomenclature applied to equine nonseptic lower airway diseases, with the aims of reducing confusion and clarifying communication between and amongst veterinary professionals and the horse-owning public [1,2]. The adoption of ‘equine asthma’ as a wide encompassing phenotypic definition of environmental airway disease recognises both the overlap between, and the features specific to, various nonseptic lower airway conditions which have, until now, generally been regarded as ‘stand alone’ disorders. Currently, this initiative mostly applies to the conditions previously termed inflammatory airway disease (IAD) and recurrent airway obstruction (RAO; including summer pasture associated RAO), both of which share certain clinical, pathological and aetiological characteristics, yet differ primarily with regard to the presence or absence of respiratory effort at rest [2–4]. Furthermore, through the application of advanced clinical and research tools, there is increasing awareness that fulfilment of the criteria used to define both the RAO and IAD can be achieved via a diverse range of aetiological triggers, molecular pathways and genetic predispositions, thus further hampering any attempt to accurately ‘pigeon hole’ these diseases as distinct entities. The term ‘equi' ...