Treatment of Idiopathic Headshaking in Horses with Pulsed High‐Dose Dexamethasone

BACKGROUND: Treatment of idiopathic headshaking in horses is complicated by an incomplete understanding of underlying pathophysiology and partially effective treatments. If an inflammatory etiology exists, corticosteroids could be beneficial. HYPOTHESIS: An anti‐inflammatory dose of dexamethasone reduces the signs of idiopathic headshaking in a field setting. ANIMALS: Convenience sample of 20 adult horses with idiopathic headshaking syndrome. Cases were recruited from the general population and diagnosed by attending veterinarians. METHODS: Prospective, blinded clinical trial. Pulsed dosing was with oral dexamethasone (60 mg PO Q24h × 4 days, q3 weeks for 4 months) or placebo (inert paste). Owners were blinded and asked to score the headshaking from 0 to 4 (4 = most severe) 3 days per week. The change in headshaking scores (HS) over each treatment pulse was compared between groups by ordinal logistic regression. RESULTS: Twelve horses completed the trial. There was no significant difference between treated or placebo horses (P = .987). Sun (P ≤ .001), wind (P = .028), and exercise (P ≤ .045) significantly increased HS. CONCLUSIONS AND CLINICAL IMPORTANCE: No benefit of dexamethasone treatment was detected for idiopathic headshaking. The results confirmed previous reports of common triggers for headshaking behavior.