Sweet itch is a debilitating allergic skin condition driven by hypersensitivity to Culicoides midge bites, causing intense pruritus and self-trauma that severely affects quality of life in susceptible horses.
Sweet itch imposes severe welfare costs through constant pruritus that prevents normal behavior and rest. The self-trauma from scratching causes skin injury and secondary infection. Affected horses are in a state of chronic discomfort throughout the midge season, which can extend for six months or more in temperate climates. Rigorous midge avoidance reduces exposure but rarely eliminates symptoms entirely. The development of immunotherapy offers hope for improved long-term welfare outcomes for horses whose condition cannot be adequately controlled by avoidance alone.