Head shaking in the horse is a well recognized, common problem with no preference for age, sex or breed. Usually the problem worsens while exercising but can be seen at anytime. Diagnosis is difficult and treatment frequently unrewarding. Recently sunlight was implicated as one of the causes, resembling photic sneezing in humans. This has provided a successful way to treat some of theses horses. Causes implicated in head shaking have been:
This article deals with the diagnosis and treatment of this frustrating problem.
Certainly the first thing to try is to see if working out of the sunlight helps. If not attempt blindfolding to determine if the problem has some relationship with the brightnesss of light. It is imperitive to exhasust this avenue. Photic head shaking is poorly understood. Treatment with cyproheptidine probbly should be atttempted, even if the problem does not seem light responsive.
And exhaustive exam would include:
Occasoinally one of theses exams will turn up a significant finding but ususally the problem continues undiagnosed.
A course of cyproheptidine at 0.3 mg/kg of body weight twice daily should be attempted. If the horse was found to worsen with increasing light levels the chance of sucess is greatly increase. Improvement occurs within 24 hours of starting treatment. Fly masks with the eye area covered in shading material has been effective for these horses.
Other treatment would be to address the specific problems identified on the diagnostic work up. Other nonspecifice treatment that has occasionally been helpful is corticosteroids. This is most effective for allergic rhinitis. Fly masks that cover the ears may help is some cases. Unfortunately treatment is frequently unrewarding.