Inhalant Horse Allergens and Allergies: A Review of the Literature

Abstract

A wealth of literature exists regarding common allergies to household pets such as cat or dog. Allergy to horse, however, is infrequently discussed in the medical literature despite significant sensitization rates among urban-dwelling subjects without direct exposure to horses. A literature search was conducted in PubMed and additional references were collected from surveying the references of the pulled articles. This review summarizes aspects of IgE-mediated horse allergy including the prevalence and mechanisms for sensitization, clinical presentation, molecular characterization of the major and minor horse allergens, and the role of allergen immunotherapy. There is currently only one horse immunotherapy study showing significant improvement in clinically sensitive patients. The 1997 World Health Organization Position Paper on Immunotherapy lists horse immunotherapy among the areas needing further clinical research. Inclusion of horse into the standard allergen panel for children and adults has been supported by several authors, although further identification and characterization of horse antigens is needed to provide the most efficacious extract. As clinicians, we need to be aware of the potential cross-reactivity among the common mammalian allergens and consider the possibility of known or occult exposure to horse as a possible source of symptom exacerbation in susceptible individuals.