Changes

==Signalment & risk factors==

==Signalment & risk factors==

Although sweet itch may occur in horses of all breeds and ages, the disease has a peak age of onset of between 2 and 4 years. Most breeds are affected although sweet itch is rare in Thoroughbreds. It has suggested that genetic factors may have a role in the pathogenesis of the disease as the prevalence of sweet itch in some breeds is higher, such as Icelandic ponies and German Shire horses.  

Although sweet itch may occur in horses of all breeds and ages, the disease has a peak age of onset of between 2 and 4 years. In cases where horses have been moved to an area with a heavier insect burden clinical signs may develop in older horses. Most breeds are affected although sweet itch is rare in Thoroughbreds. It has suggested that genetic factors may have a role in the pathogenesis of the disease as the prevalence of sweet itch in some breeds is higher, such as Icelandic ponies and German Shire horses.  

''Culicoides'' require marshy areas or still water and horses kept in fields near streams or water may be at higher risk of developing sweet itch. Additionally, in order to breed successfully the midges require decaying manure and bedding, therefore poor hygiene increases the risk of sweet itch.   

''Culicoides'' require marshy areas or still water and horses kept in fields near streams or water may be at higher risk of developing sweet itch. Additionally, in order to breed successfully the midges require decaying manure and bedding, therefore poor hygiene increases the risk of sweet itch.   

==Clinical signs==

==Clinical signs==

The cardinal sign of Sweet itch is extreme, intense pruritus with characteristic distribution patterns. Commonly affected areas include the head, mane, tail, withers and ventral abdomen. Primary lesions are papules but self-excoration may lead to the characteristic lesions of sweet itch including alopecia, broken hairs, erosions, ulcers. Lesions are frequently painful and In the chronic stages, lichenification, hyperkeratosis and scaling are common features.   

The cardinal sign of Sweet itch is extreme, intense pruritus with characteristic distribution patterns. Commonly affected areas include the head, mane, tail, withers and ventral abdomen. Primary lesions are papules but self-excoration may lead to the characteristic lesions of sweet itch including alopecia, broken hairs, erosions, ulcers. Lesions are frequently painful and usually increase in severity with age. In the chronic stages, lichenification, hyperkeratosis and scaling are common features.   

==Diagnosis==

==Diagnosis==

The aims of treatment are to control pruritus, treat any secondary bacterial infections and reduce the number of midges coming into contact with the affected horse. In many cases, appropriate environmental changes are sufficient to ease clinical signs.  Anti-midge rugs are available and prevent the insects from landing and feeding and are most effective when used in conjunction with an insect repellant containing citrus extract or DEET. Access to marshy pasture or fields near open water should be prevented and horses should be stabled at night when midges are most active. Fans and anti-fly mesh may be provided in the stable to provide additional protection from midges.

The aims of treatment are to control pruritus, treat any secondary bacterial infections and reduce the number of midges coming into contact with the affected horse. In many cases, appropriate environmental changes are sufficient to ease clinical signs.  Anti-midge rugs are available and prevent the insects from landing and feeding and are most effective when used in conjunction with an insect repellant containing citrus extract or DEET. Access to marshy pasture or fields near open water should be prevented and horses should be stabled at night when midges are most active. Fans and anti-fly mesh may be provided in the stable to provide additional protection from midges.

In severe cases, further treatment using corticosteroids to reduce inflammation and pruritus may be required. These should be used with caution in order to avoid possible side-effects including laminitis and iatrogenic hyperadrenocorticism. Antihistamines may be beneficial as a more long-term method of control but are only useful if administered before the onset of pruritus. Omega 3 and 6 fatty acids may aid in reducing pruritus and  

In severe cases, further treatment using corticosteroids to reduce inflammation and pruritus may be required. These should be used with caution in order to avoid possible side-effects including laminitis and iatrogenic hyperadrenocorticism. Antihistamines may be beneficial as a more long-term method of control but are only useful if administered before the onset of pruritus. Omega 3 and 6 fatty acids may aid in reducing pruritus and controlling inflammation.

 

==References==

==References==