Summer eczema is a known problem with ponies, horses, miniature horses and Shetland pigs. More and more horses are suffering from summer eczema. The itching is caused by a small mosquito. When this mosquito pricks a horse, it leaves some saliva. Horses that are sensitive to summer eczema have an allergic reaction to this. This allergic reaction causes terrible itching. Summer eczema is hardly ever seen in young horses and ponies. Often summer eczema only appears from about 2-3 years after which it can get worse every year. This applies to horses, ponies, miniature horses and Shetland ponies.