Sweet itch

Sweet itch is an allergic disease.

Cause
It is now thought that sweet itch is probably an immediate hypersensitive reaction to the saliva of midges of the Culicoides group. This disease occur in the sommer when the midges are active.

Symptoms
The intense irritation makes the horse rub the areas bitten by the midge, usually the mane and tail. In the early stages, the skin becomes very thickened and oedematous. The hair in these areas quickly becomes thin and tufted and many papules develop, oozing small blobs of serum onto the surface.
As the itch becomes worse and the rubbing constant, the hair of the mane and tail is completely lost and the skin develops a corrugated appearance, becoming ridged and scaly.

Treatment
Treatment really depends on preventing the midges biting the horse. Besides the use of insect repellents, this involves stabling the horse during those times that the midges are most active (the first and last few hours of daylight). In severe cases the has to be stabled with a mosquito netting protecting the stable.
Lotions and remedies have been used: Benzyl Benzoate applied to the affected areas is soothing and may be a deterrent, Caladryl, coal-tar lotions all have their advocates but they suffer from the same drawback - their effect is temporary, and daily application is necessary. Moreover unless some effort is made to prevent the midges biting, all these local and parental treatments will continue to be of limited use.
Corticosteroids and antihistamine preparations are the most widely used. They need frequent application and are costly. Longacting corticosteroid injections are the most useful for controlling the intense reactions present.