Sweet Itch

What is Sweet-itch?
Sweet itch is a non-contagious pruritic dermatitis that occurs in horses allergic to the saliva of Culicoides midges. In the UK, the sweet itch season can go from April to September depending on warm weather. Ponies and Shire breeds are more susceptible to it but it can affect all kind of horses, ages and sexes. Usually the problem gets worse with age, and there is no clear hereditary component.

We can help you tell if your pony has got sweet itch. First, we will have to rule out all forma of ectoparasites (parasites that live on the skin) that can cause dermatitis. Typically, sweet itch lesions run along the mane, back and base of the tail. They are characterised by inflamed skin, which causes intense itching. Horses will bite or rub their back end on gates, posts and trees, harming themselves. In chronic cases, the skin becomes thickened, crusty and hairless.

How can I control it?
The most effective way to control sweet itch is to try to avoid the midges by using insect repellents (as pour –on or cattle ear tags) or physical barriers (blankets and masks). Making your horse graze late at night or early morning will help avoid getting him bitten, as the Culicoides midges are most active 1 hour before dusk.

As therapy, the administration of glucocorticoids is still the most effective. However, it is not recommendable to use them in some cases or long term, because of various systemic side effects. Immunotherapy/hyposensitisation, is another option of treatment that works long term in about half of the cases. It consists on getting the horse’s immune system used to the Culicoides antigen by injecting increasing doses of it into the skin. It is easy to do but needs owner commitment, specially the first month of treatment.