Sweet itch is a chronic, intensely pruritic allergic skin condition in horses caused by Culicoides midge bites. Without management, it causes severe welfare harm and self-mutilation.
Sweet itch causes chronic intense suffering that significantly impairs quality of life for affected horses. The level of pruritus experienced drives horses to rub against any available surface with such intensity that they cause significant self-injury — hair loss, skin excoriations, and bloody lesions. The condition is present throughout the midge season, meaning months of ongoing distress without management. Effective management requires comprehensive midge avoidance: stabling during peak midge activity (dawn and dusk), full-body fly rugs including head and belly coverage, and application of appropriate insect repellents. Medical management using antihistamines or corticosteroids may be needed for severe cases. Emerging immunotherapy options may eventually offer more effective control. No horse with sweet itch should be left unmanaged.