The sunny days have arrived, along with all kinds of biting insects coming to give a hard time to our mounts.
Some of them can cause typical skin problems, as for example equine recurring summer dermatitis, or DERE.

This skin inflammation is due to an allergic reaction of the horse to allergenic proteins, toxins, and anticoagulants contained in the saliva of the biting insects.

All horses are not allergic: it looks like this tendency to react more or less to allergens has a family or hereditary origin, although no gene has been clearly identified.

When bitten, the allergic horse develops a series of chain reactions, some immediate (e.g. release of inflammatory agents), some appearing later on (e.g. inflammatory cells migrating into the thickness of the skin). The symptoms may therefore last much longer than the bite.

These highly itchy allergic reactions lead to the first symptoms, characterized by an important urge to scratch against any support. This behavior induces secondary symptoms: skin alteration, epidermal stripping, scales, and skin ulceration, the latest becoming thick and unyielding.

These secondary lesions mainly affect the areas of the neckline, head, underline and rump. They are particularly dramatic on the mane and tail, which can be totally scratched off and bald.
These skin ailments are usually seasonal, since they are due to the presence of biting insects. However, the symptoms can last longer because of a long-lasting skin thickening.

How to act against the equine summer dermatitis?


The horse has natural fly-whisks to protect itself against insects: its mane and tail. One should therefore avoid cutting its tuft, hair and tail during summer time.
Another horse can also be placed head-to-tail, so that they can help each other chase the insects away.

The risks of meeting insects can also be limited as much as possible for the horse:

  • By choosing pasture far from streams or still water, which favor the development of larvae or insects;
  • By choosing ventilated pasture where insects will be less numerous;
  • By covering the horses with mosquito nets
  • By bringing the horses inside during peaks in insect activity (sunrise, evening);
  • By protecting the horses with repulsive products;
  • By covering the sensitive areas with a thin layer of Manicougan clay and letting it dry.


By acting rapidly from onset of symptoms to avoid infectious complications:

  • By using Active Soap, an antiseptic soap which will help reduce the risks of infection, stop the itches and rebuild the skin tissue.

In case of more developed symptoms, a veterinarian should be visited for more advice.