Sweet itch affects approximately 5% of horses worldwide, with strong genetic predisposition determining which individuals are hypersensitive to Culicoides midge bites and at risk of severe seasonal suffering.
Sweet itch causes extreme, chronic suffering during peak midge seasons: affected horses rub mane, tail, and body against any available surface, sometimes until skin bleeds, then rub again compulsively driven by overwhelming itch. The condition is not merely uncomfortable - for severe cases, the constant itch-rub cycle prevents rest, disrupts eating, and causes secondary wounds. Management requires multi-pronged, vigilant approach (rugs, stabling at dawn/dusk, insect repellents, antihistamines) that significantly restricts normal horse behavior. Breeding decisions matter enormously - selecting sweet itch-positive stallions or mares for breeding passes on a welfare burden to offspring. The condition is also financially burdensome, adding to the risk that affected horses are neglected or surrendered when management becomes overwhelming.