Culicoides Hypersensitivity, also known as Sweet Itch, is a condition caused by an allergic reaction to the saliva of Culicoides species known as "No See Ums." Horses with this hypersensitivity are extremely pruritic or itchy. They will rub their manes, ears, faces, and tails to the point of self-mutilation. Typically signs are seen during warmer months. There are multiple treatments recommended but not all are rewarding. Fly sprays and sheets can help reduce exposure. Antihistamines and steroids can help reduce severity of signs in some horses. Supplements high in fatty acids may help skin health. Also reducing standing water and providing fans in stall areas can help. However, the most rewarding form of treatment is immunotherapy (allergy shots).
This horse presented for progressively worsening signs of pruritis and self mutilation. Initial treatments with antihistamines and steroids as well as fly sprays and sheets did little to help alleviate his signs.
Serum allergy testing confirmed that he had a hypersensitivity to Culicoides. Immunotherapy shots were administered over the course of 6 months and discontinued in the winter time. He was seen for routine vaccinations this spring. He is no longer self mutilating. If any signs return, the immunotherapy shots will be administered again.