Is inhaled immunotherapy more effective than environmental management when treating equine asthma?



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PICO question

In horses with severe equine asthma syndrome, is inhaled immunotherapy compared to environmental reduction of allergen exposure more effective in disease modification?


Clinical bottom line

Category of research question


The number and type of study designs reviewed

12 papers were critically reviewed. Nine clinical trials; one crossover study; one split-plot design study; and one cross-sectional study

Strength of evidence


Outcomes reported

Four studies found inhaled immunotherapy to improve the clinical signs associated with equine asthma and the lung function of horses with asthma. Three papers found environmental modification improved lung function and the clinical signs associated with equine asthma but two studies provide moderate evidence that environmental management alone is insufficient to permanently cure asthma


There is a low level of evidence to support the use of inhaled immunotherapy as a treatment for equine asthma


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


Open Access Peer Reviewed


Auger, E. & Moore-Colyer, M. (2017). The Effect of Management Regime on Airborne Respirable Dust Concentrations in Two Different Types of Horse Stable Design. Journal of Equine Veterinary Science. 51, 105–109. DOI:

Barton, A., Shety, T., Klier, J., Geis, S., Einspanier, R. & Gehlen, H. (2019). Metalloproteinases and their Inhibitors under the Course of Immunostimulation by CPG-ODN and Specific Antigen Inhalation in Equine Asthma. Mediators of Inflammation. 2019, 1–7. DOI:

Beech, J. & Merryman, G. (1986). Immunotherapy for equine respiratory disease. Journal of Equine Veterinary Science. 6(1), 6–10. DOI:

Cornelisse, C. & Robinson, N. (2011). Glucocorticoid therapy and the risk of equine laminitis. Equine Veterinary Education. 25(1), 39–46. DOI:

Couëtil, L., Cardwell, J., Gerber, V., Lavoie, J., Léguillette, R. & Richard, E. (2016). Inflammatory Airway Disease of Horses-Revised Consensus Statement. Journal of Veterinary Internal Medicine. 30(2), 503–515. DOI:

Couëtil, L., Chilcoat, C., DeNicola, D., Clark, S., Glickman, N. & Glickman, L. (2005). Randomized, controlled study of inhaled fluticasone propionate, oral administration of prednisone, and environmental management of horses with recurrent airway obstruction. American Journal of Veterinary Research. 66(10), 1665­–1674. DOI:

Jackson, C., Berney, C., Jefcoat, A. & Robinson, N. (2010). Environment and prednisone interactions in the treatment of recurrent airway obstruction (heaves). Equine Veterinary Journal. 32(5), 432–438. DOI:

Klier, J., Bartl, C., Geuder, S., Geh, K., Reese, S., Goehring, L., Winter, G. & Gehlen, H. (2019). Immunomodulatory asthma therapy in the equine animal model: A dose‐response study and evaluation of a long‐term effect. Immunity, Inflammation and Disease. 7(3), 130–149. DOI:

Klier, J., Fuchs, S., May, A., Schillinger, U., Plank, C., Winter, G., Gehlen, H. & Coester, C. (2012). A Nebulized Gelatin Nanoparticle-Based CpG Formulation is Effective in Immunotherapy of Allergic Horses. Pharmaceutical Research. 29(6), 1650–1657. DOI:

Klier, J., Geis, S., Steuer, J., Geh, K., Reese, S., Fuchs, S., Mueller, R., Winter, G. & Gehlen, H. (2017). A comparison of nanoparticulate CpG immunotherapy with and without allergens in spontaneously equine asthma‐affected horses, an animal model. Immunity, Inflammation and Disease. 6(1), 81–96. DOI:

Klier, J., Lehmann, B., Fuchs, S., Reese, S., Hirschmann, A., Coester, C., Winter, G. & Gehlen, H. (2015). Nanoparticulate CpG Immunotherapy in RAO-Affected Horses: Phase I and IIa Study. Journal of Veterinary Internal Medicine. 29(1), 286–293. DOI:

Lavoie, J.‐P., Bullone, M., Rodrigues, N., Germim, P., Albrecht, B. & von Salis‐Soglio, M. (2019). Effect of different doses of inhaled ciclesonide on lung function, clinical signs related to airflow limitation and serum cortisol levels in horses with experimentally induced mild to severe airway obstruction. Equine Veterinary Journal. 51(6), 779–786. DOI:

Leclere, M., Lavoie-Lamoureux, A., Gélinas-Lymburner, E., David, F., Martin, J.G. & Lavoie, J.P. (2011). Effect of antigenic exposure on airway smooth muscle remodeling in an equine model of chronic asthma. American Journal of Respiratory Cell and Molecular Biology. 45(1), 181–187. DOI:

Leclere, M., Lavoie-Lamoureux, A., Joubert, P., Relave, F., Setlakwe, E.L., Beauchamp, G., Couture, C., Martin, J.G. & Lavoie, J.P. (2012). Corticosteroids and antigen avoidance decrease airway smooth muscle mass in an equine asthma model. American Journal of Respiratory Cell and Molecular Biology. 47(5), 589–96. DOI:

Miskovic, M., Couëtil, L. & Thompson, C. (2008). Lung Function and Airway Cytologic Profiles in Horses with Recurrent Airway Obstruction Maintained in Low-Dust Environments. Journal of Veterinary Internal Medicine. 21(5), 1060–1066. DOI:

Simões, J., Sales Luís, J. & Tilley, P. (2020). Owner Compliance to an Environmental Management Protocol for Severe Equine Asthma Syndrome. Journal of Equine Veterinary Science. 87, 102937. DOI:

Vandenput, S., Duvivier, D., Votion, D., Art, T. & Lekeux, P. (2010). Environmental control to maintain stabled COPD horses in clinical remission: effects on pulmonary function. Equine Veterinary Journal. 30(2), 93–96. DOI:

Vol. 6 No. 1 (2021): The first issue of 2021

Section: Knowledge Summaries

Categories :  Small Animal  /  Dogs  /  Cats  /  Rabbits  /  Production Animal  /  Cattle  /  Sheep  /  Pig  /  Equine  /