Sweet itch is a severely debilitating allergic skin condition in horses caused by hypersensitivity to Culicoides midge bites, with significant genetic components influencing breed susceptibility.
Sweet itch causes intense, chronic suffering that is often underestimated by those who have not witnessed severely affected horses. The constant urge to rub leads to raw, bleeding skin, distorted mane and tail, and secondary infection. The genetic dimension raises important breeding ethics questions: horses known to carry sweet itch susceptibility should not be bred without informed consideration of the welfare burden being perpetuated. Beyond breeding, affected horses require comprehensive year-round management — specialist rugs, strategic stabling, insect repellents, and potentially medical treatment — to achieve acceptable quality of life. Improved genetic understanding may eventually enable selective breeding that reduces prevalence in susceptible populations.