Is Sweet Itch Driving Your Horse Crazy? Presented by Kentucky Performance Products

It’s that time of year again. When summer sweet itch — or summer itch — will drive your horse crazy. Here are some tips to keep your four-legged pal (and you!) sane now that fly season is in full swing.


Summer seasonal recurrent dermatitis (SSRD), commonly called sweet itch or summer itch, is caused by a horse’s allergic reaction to the saliva of a biting gnat known as the Culicoides midge. Many people refer to them as “no-see-ums.” These bothersome fellows are active from April through October. They live and breed in ponds, marshes, and areas where water is standing and stagnant. Gnats can travel up to half a mile to find a good meal. They tend to be most active during the hours around dawn and dusk.

It takes about 48 to 72 hours after the first gnat bite for your horse to start showing symptoms. The severity of the reaction increases from year to year, as your horse becomes increasingly more sensitive to the insect’s saliva. Dorsal feeders are the most common gnat; they feed on the skin around the ears, poll, mane, withers, rump, and tail head. Less common are the ventral feeders, who cause problems on the face, chest, and belly.


The symptoms of SSRD or sweet itch are hard to miss. Horses will constantly rub affected areas as a response to the intense itching. In the acute phase (early phase) the skin will become red and inflamed, and devoid of hair. Crusting and weeping sores may be present. In the chronic phase (later phase) the skin will thicken, blacken and become wrinkled. Sparse, course hair may be present. Once winter comes, the area completely heals up.

There are several measures you can take to limit your horse’s exposure to these annoying insects.

  • Install fine mesh screen in your barn to keep the gnats out. (This is not always practical, however.)
  • Circulate the air with ceiling and stall fans to discourage the gnats from hanging around.
  • Keep horses stalled an hour prior to and after dawn and dusk to reduce exposure to the bugs when they are most actively feeding.
  • Keep stables at least a half mile away from marshes and swamps.
  • Ensure pastures are well-drained to reduce stagnant water from collecting.
  • Keep water tanks clean and filled with fresh water.
  • Use insecticides and repellents to kill gnats and keep them off your horse.
  • Use a fly sheet with tail flap and hood to cover vulnerable areas.

Treatment and prevention

The sooner you notice sweet itch and start on a program of treatment and prevention the better off your horse will be. A horse can do a lot of damage in a short period of time when they start rubbing manes and tails.

When you first notice symptoms, take immediate action to reduce your horse’s exposure to these nasty gnats by following the recommendations above. Contact your vet and ask him or her about corticosteroid and antihistamine treatments.

Coating the itchy area daily with an oily substance, like baby oil or Skin So Soft, is often beneficial. Midges don’t like the oily film and will avoid it. Be sure to reapply the oil often, as it tends to wear off as the day goes on.

Be careful with preparations that contain eucalyptus oil, citronella oil, tea tree oil, or mineral oil, as they may cause additional skin irritation. Try them somewhere else on your horse first. Watch the area for 24 hours, noting the appearance of any heat or swelling. Don’t use any preparation that causes irritation.

Supplementing with omega-3 fatty acids has been proven to reduce skin inflammation and mitigate allergic response. Fish oils contain the highest level of beneficial omega-3 fatty acids. When adding a fish oil supplement to your horse’s diet, do so slowly. Add a small amount at a time. In the beginning pour the oil on the feed and let it sit for 30 minutes before mixing it in so the smell is less powerful. Most horses will readily eat fish oil once they become accustomed to the new flavor.

About Kentucky Performance Products, LLC:

Summer Games® Electrolyte

  • Replenishes critical electrolytes in the proper ratios.
  • Supports drinking and maintains hydration.

Summer Games contains a research-proven electrolyte formulation that was originally developed for the horses competing at the 1996 Olympics. Formulated using the results of extensive research studies investigating the composition of sweat, Summer Games contains both key electrolytes and trace minerals in the actual amounts that are present in the sweat.

Learn more about the importance of hydration here.