Sweet Itch also known as Summer Seasonal Recurrent Dermatitis or Queensland Itch is an allergic reaction (Hypersensitivity) to proteins in the saliva of a specific type of midge known as Culicoides. Both type 1 (immediate) and type IV (delayed) hypersensitivity reactions occur with Type 1 hypersensitivity being the primary reaction which results in the release of Histamine.

 

Clinical signs of Sweet Itch tend to be found along the dorsal midline including the head, ears, saddle region, rump and tail. In severe cases it may also include the facial area and along the ventral including the chest, abdomen and upper forelegs. These symptoms include Pruritus resulting in lesions caused by self-trauma as well as scaling, crusting, hair loss, intense itchy dermatitis, excessive dandruff, hyper pigmentation, skin thickening and skin ridging.

 

Sweet itch is known to affect up to 10% of horses and ponies in the UK, it is also found in Australia, Canada, USA and other areas around the world and it is suspected that there is a genetic predisposition.