Summer eczema and allergies in horsesWith the warm temperatures, the annual itching and scratching begins for some horses. What exactly is sweet itch and what can be done about it??
Allergic reactions can basically be triggered by many different substances. Pasture. Symptoms range from swelling of the skin. Mucous membrane over disturbed general condition up to respiratory tract complaints. Symptoms range from swelling of the skin. mucous membrane over disturbed general condition up to respiratory problems. In chronic allergies such as sweet itch, constant itching is often a central problem. The horses try to rub themselves everywhere. Suffering from the excruciating itch. The often completely abraded mane and a frayed tail are not only a visual problem – they are also lacking in the defense against the annoying gnats and flies.
Young stallion with urticaria (hives), an acute allergic reaction to an as yet unknown allergen. In urticaria, raised wheals form, but the skin remains intact.
The Sweet itch is an allergic reaction to the saliva of mosquitoes. At the age of 3-6 years first symptoms can appear. As the dog ages, the reaction generally becomes more severe. During the winter months, even severely affected horses recover because the causative mosquitoes are not active. The typical spots are Mane, tail, lower chest and belly where hairlessness, scaling, crusting and exudation are present. The intense itching can even lead to self-mutilation.
Bald patches, thickening of the skin and crusty changes in places are symptoms of sweet itch. Source: Horse and Hound
In order to get the agonizing itching under control, the cause must be investigated. There are several ways to do this: Allergy tests can exclude various allergens such as grasses, pollen, insects, fungal spores or various feeds. If thus the cause was found can then z.B. a hyposensitization therapy can be started. In the case of Diagnosis of exclusion If the patient is exposed to a certain allergen over a longer period of time (e.g.B. mosquitoes, food) kept away. If the symptoms subside, there is a high probability that the cause has been found. If the following key points apply, the diagnosis is sweet itch very likely: the horses recover during the winter months, the symptoms reappear with the beginning of the mosquito season and keeping the mosquitoes away again alleviates the symptoms.
Allergen avoidance – that is, protection from the substances that trigger an allergy – is the most important measure. This is often the most effective way to avoid the need for drug therapy. In the case of sweet itch these are Full body blankets, insect repellents and the Stabling during the main flight periods of insects. Cortisone as an anti-inflammatory. Itch-relieving substance. But also histamine blockers, which are also used by people with hay fever, are used in some cases. In addition to these systemic therapies, the following can and should also be used locally applicable products should be used. Experience has shown that antipruritic, calming Shampoos and lotions with oat extracts have a good effect. If there are already severe skin changes, regular wound treatment must be carried out in any case.
A therapy already mentioned above is ASIT therapy (allergen-specific immunotherapy), also Hyposensitization called. Based on an allergy test, the immune system is accustomed to increasing allergen concentrations. This modulates the cell response of the immune system, which can reduce an allergic reaction of the body. For horses with sweet itch, it is best to start on the end of the mosquito season can be started with the therapy. Before the start of the next grazing season, the horse's immune system is then optimally prepared for the "insect plague". The success rate of ASIT therapy is between 70% and 80%!
A vaccine against sweet itch is under development!
At the Universities of Bern and Zurich, intensive work is being done to Insect hypersensitivity vaccine worked. The vaccine fights the allergy-causing eosinophils by binding specific inflammatory markers (interleukin 5). Of the 19 horses vaccinated, the vaccine was well tolerated. The skin lesions were 50-75% less pronounced than in the previous year. You can download the complete study under the following link. It should not be long before the vaccination is available, but unfortunately an exact date has not yet been determined.