Equine Headshaking Syndrome: Triggers, Seasonality, and Treatment Efficacy in Australia.

Equine headshaking syndrome is a poorly understood neuropathic pain condition presenting as uncontrollable shaking, flicking, or striking of the head. Therapeutic options are limited, and treatments are only partially successful. Currently, epidemiological information on headshaking in the Southern Hemisphere is lacking. An online survey was circulated to Australian owners of headshaking horses to collect information on triggers, symptoms, seasonality, treatments, and perceived treatment efficacy. The responses (n = 216) showed the mean age at symptom onset as 9.6 (±4.7) years. More geldings were affected than mares (76% vs. 24%), and symptom onset occurred later in geldings compared to mares (10.1 ± 4.7 vs. 7.9 ± 4.0 years; < 0.01). Bright sunlight, wind, and high pollen were the most commonly reported triggers (61%, 46% and 40%, respectively), and seasonal onset of symptoms was reported by 54% of respondents. In total, 71% of respondents reported using two or more treatments. The most common treatments were supplements (68%), nose nets (63%), light-blocking masks (48%), bodywork (48%) and pharmaceutical compounds (38%). Overall, treatments were considered ineffective by 33% of respondents. The findings were in agreement with surveys from the Northern Hemisphere. Of note was the perception of bright light as a primary trigger, alongside the reported low treatment efficacy of light-blocking masks. Seasonal intensification of symptoms and its relationship to day length merits further exploration.