Insect Bite Hypersensitivity, also commonly known as QLD Itch or sweet itch, is the most common allergic skin disease in horses. It is caused by an allergic reaction to Culicoides spp. biting midges, resulting in chronic, relapsing, seasonal dermatitis. Clinical signs are more severe in warmer months, when Culicoides spp. are most active.
The clinical signs commonly seen in horses include:
- Inflammation of the skin
- Crusts and scale
- Itchy skin
- Hair loss
- Secondary infections
Horses with QLD Itch may be seen biting, scratching or rubbing against objects to relieve their itch. The body regions affected will depend on the preferred feeding sites of Culicoides spp. found in the area. Commonly affected areas include the face, ears, poll, crest, tail, back and abdomen.
A veterinary consultation is essential in the diagnosis and treatment of insect bite hypersensitivity. Diagnosis should be based on history, clinical examination, distribution of lesions, ruling out other causes of pruritus and response to insect control. Talk to your veterinarian to discuss what treatment and management options would be most appropriate for your pet.