Urticaria or hives is the development of small lumps on your horse’s skin caused by an allergic reaction to a change in feed, midge bites, or reaction to certain chemicals or allergens. The episodes may be limited to one or two occurrences that respond to treatment or may become recurrent episodes that require further investigation.
Horses showing signs of Urticaria may have welts or lumps over limited parts of their body extending to the whole body, they may itch profusely, have swollen lips or eyelids, elevated temperature, rapid breathing and be hot to the touch.
Sweet itch is a common seasonal dermatosis that occurs mainly in summer due to a hypersensitivity to biting midges. These midges, called Culicoides midges are the same midges that carry African Horse Sickness.
How can I prevent midges biting my horse?
As many of you are probably aware, a large part of the prevention of horse sickness lies in vector protection. In other words the stringent use of midge repellents and control methods can deter midges and flies. Since midges are not flies however, common fly sprays are not adequate in warding off these little critters and the use of midge repellent substances are strongly recommended.
How can I treat sweet itch?
Since this is an allergic irritation, there is no cure. However; there are a number of ways in which to provide some relief for those very itchy, irritated horses. It is important to differentiate between midge bite hypersensitivity and other causes of Urticaria such as feed sensitivity and/or fynbos allergies.
The first step in controlling the allergy is to reduce the number of bites from the midges. This is done in a number of ways:
Severely itchy horses may require medical intervention in order to minimise scratching and rubbing and causing injury to the skin of the itchy areas. These treatments would include the use of systemic cortisone injections as well as topical creams, lotions and/or shampoos. Please consult your vet in this case.
Benzyl Benzoate is an effective remedy for mites that cause mange (see later), but can be used successfully to control sweet itch. It is a skin irritant however and should thus only be used in cases prior to the onset of hair loss and raw sores. If used on very irritated, sensitive skin it may worsen the condition and lead to skin sloughing.
The use of fly sheets is a very effective way in which to decrease midge attacks and eliminates the need for insecticides and oils or greases.
Effective management of Sweet Itch is difficult, frustrating and relies solely on the decline in midge numbers for resolution. However it is seasonal and if your horse has it one year it is likely to get it every year. Should you have any concerns regarding your horse’s condition please chat to one of our vets.
Sweet itch vs Grasss Mange
Mange refers to the infestation of the skin and hair by a biting mite. These mites are found during the dry summer months in the long grass and attach to the horses hair as contact is made. There are many species of mite that may cause a problem but the most serious is Sarcoptes spp. Because infestation often starts on the neck and face it is commonly confused with sweet itch. Itchy patches become hairless and if left untreated, the skin over time becomes bare, wrinkled and covered in crusts.
Treatment involves washing with an insecticidal shampoo; however in severe cases veterinary treatment may be required.