You are currently viewing Grass allergies
Some horses may have allergies to biting insects. These issues need to be handled with care.

Grass allergies

Some horses may have allergies to biting insects. These issues need to be handled with care.
Some horses may have allergies to biting insects. These issues need to be handled with care.

Along with our glorious summer weather comes the dreaded mange for those whose horses are susceptible. Seemingly overnight, sleek shiny horses can turn into dull-coated, itching shadows of their former selves. It can be every proud owner’s nightmare and it’s certainly no fun for the horse either. Imagine being covered in millions of tiny mosquito bites, and you will get an idea of how a horse suffering from an itchy skin condition feels.


Mange is the common name given to parasitic skin diseases caused by mites (arthropods – eight-legged parasites), which cause intense itching and hair loss in the horse. Mites are most active during the hot, dry summer months and can be found on long grass where they are picked up when contact is made. When the mite attaches itself to the horse’s legs and/or face it injects a fluid into the horse’s tissue which causes irritation and discomfort. The mite will remain on the horse’s skin for a few days before dropping to the ground where it then burrows into the soil and matures into an adult after six weeks.

There are five main types of mange that can affect horses and all require careful and thorough treatment:

  • Sarcoptic mange
  • Psoroptic mange
  • Chorioptic mange or leg mange
  • Demodectic mange
  • Straw itch mite or forage mite


  • Hair loss
  • Itching and rubbing
  • Stamping of the feet and shaking of the head
  • Inflammation of the skin


This varies, so discuss it with your vet. It normally involves scrubbing the area with an insecticide horse shampoo repeated weekly or every second week, or the application of an anti-inflammatory antiseptic cream or spray. Your vet may prescribe antibiotics if it is a severe infestation.

Your vet may also administer an injection to destroy any deeply laid mange eggs buried within the horse’s skin.

Sweet itch

Sweet itch is caused by a reaction to the saliva in the Culicoides midge bite. Alternative names for sweet itch are insect bite hypersensitivity (IBH), Queensland itch, equine summer itch and summer seasonal recurrent dermatitis (SSRD).

Sweet itch shows intense itching followed by ulceration and thickening of the skin as the horse’s immune system tries to re-balance the body’s over-reaction to the bite.


Fly sheets can provide protection against insects
Fly sheets can provide protection against insects

Prevention here is vital as there seems to be no known cure for sweet itch. Fly rugs or insect protection rugs are really important to prevent or limit the bites that a horse experiences.

Midges love rotting vegetation, long grass and standing water. Keep grass short and the yard and paddocks as clean, dry and well cut as possible.

Subsequently, treatment is focused on reducing the itching and discomfort that the horse experiences. Medicines such as corticosteroids and anti-histamines require assistance and a prescription from your vet.

Many horse owners swear by herbal remedies and one that pops up regularly in connection with sweet itch is Global Herbs Skratch Plus, which is available in South Africa.

Head-shaking syndrome

Head-shaking syndrome has to be one of the most heartbreaking issues to deal with in horses. It is an incredibly complex syndrome with no definitive answers yet. One of the theories is that seasonal allergies have an impact on horses who suffer from this syndrome. Swollen eyes, nose rubbing and violent head-jerking are all symptoms. This syndrome is not related to allergies alone, and the volume of information surrounding it is vast.

Professional advice

This is a syndrome that definitely relies heavily on support from your vet and other professionals. It may involve all sorts of experimentation and lateral thinking to try and identify what your horse’s triggers are.

Stay informed

With seasonal irritations, allergies and sensitivities, recognition and prevention are far more beneficial than treatment. Keeping a diary helps to identify the seasonal triggers and warning signs, helping you to prevent the next outbreak. Bug rugs, fly sprays and numerous other products become you and your horse’s new best friends while you work to beat the long-grass blues.

Text: Mandy Schroder
The full article appears in the October issue of HQ.