Sweet Itch in Horses: Signs & Management Methods

Sweet itch in horses is one of the most common skin diseases and affects around five per cent of the UK’s equine population. Also known as Summer Seasonal Recurrent Dermatitis or Equine Insect Bite Hypersensitivity, the condition is a lifelong, irritating issue which requires careful management to ensure your horse has the best possible quality of life.

What is sweet itch in horses?

Sweet itch is an allergic reaction which is caused by the saliva found in mosquito and midge bites. In the UK it’s generally caused by either the black fly (Simulium) or the midge (Culicoides). These bites tend to become extremely itchy which is known as pruritis, the sensation which makes them bite, scratch and rub at their skin.

The condition can vary greatly depending on the horse in question and can range from the occasional tail scratch to obsessive scratching to the point of self-trauma.

When does sweet itch usually occur?

You may have heard of sweet itch in horses being a summer-specific condition, but it can actually occur as early as March and last as late as November. When it develops all depends on when the biting insects are most active, which is typically when temperatures are consistently over the 10°c mark.

Are some breeds more affected than others?

Sweet itch can affect any horse, regardless of breed or age, but some types do seem to be more susceptible to it. Ponies and cobs in general, especially natives tend to be more at risk, such as Exmoor, Welsh, Shetlands, and Connemaras. It’s unclear why it’s more common in these breeds.

Signs of sweet itch in horses

The signs of sweet itch in horses are usually seen at the base of their mane, tail and on their face as these are the most common spots where biting insects will feed. Their withers, back, stomach and rump may also be affected. Symptoms can vary widely and tend to be worse in hot, humid weather and around dawn and dusk when the midges and mosquitoes are most active.

 

• Extreme itchiness: horses may scratch themselves on anything available such as trees, fence posts and stable doors
• Lumpy or scaly areas which may be inflamed or hot to the touch
• Areas where the hair has been ruffled or rubbed
• Hair loss, bleeding and thickening of the skin may develop from scratching
• Excessive mutual grooming from field mates
• Consistent rolling and attempting to scratch their mane with the hind hooves

 

If you spot any of the above signs of sweet itch in horses, contact your vet as soon as possible for diagnosis. It’s important to note that the signs listed above can also be seen in other allergic skin conditions so correct diagnosis and treatment are key in helping your horse.

Diagnosing sweet itch in horses

In some cases, sweet itch can be diagnosed on just the clinical signs alone, but your vet may want to carry out intradermal allergy testing to confirm. During testing, midge extracts will be injected into the skin and the site will then be observed to see if a reaction develops. They’ll also detect for other allergies during this time to narrow down any other potential causes.

Sweet itch treatment methods

At present, there’s no real cure for the skin condition, so sweet itch treatment relies on management methods which are most effective when caught and carried out earlier on. Here are some of the best sweet itch management methods that your vet may suggest:

1. Invest in a good fly rug

Horses with sweet itch will likely have to wear a fly rug 24/7, so it’s well worth investing in a good quality one that fits well. There’s a huge range of options available including ones with neck, tail and belly covers and some will cover every single part of your horse to offer the best possible protection against biting insects.

2. Use fly repellent

A good fly spray is worth its weight in gold for sweet itch sufferers. Look for an option which specifically targets mosquitoes and midges and products that contain pyrethroid or permethrin-based ingredients as these tend to be quite effective.

3. Don’t turn them out during active times

Prevention is better than a cure, so limiting your horse’s exposure to midges and mosquitos is by far one of the most effective management methods. Biting insects tend to be most active during dawn and dusk, so it may be best to keep your horse stabled during these times. You may also want to insect-proof your stable block by buying mesh for windows and stable doors to prevent them from getting in, using a horse-friendly insecticidal spray, and installing fans as midges are poor fliers in wind.

4. Manage their paddock carefully

If you turn your horse out, you’ll need to evaluate their paddock carefully. The midge population is always greater near watercourses as their developmental life stages rely on the presence of water to create a warm and moist environment. The best paddocks for sweet itch sufferers are hilltop paddocks which are naturally windswept, away from watercourses and without thick sheltering to block airflow.

You’ll also want to clean water troughs regularly to prevent stagnant water from accumulating. Additionally, poo picking daily and ensuring the muck heap is away from fields is very important as midges love the moist environment of droppings.

5. Try adding skin supplements to their food

It’s possible that skin supplements can help alleviate itching in horses, so they may be effective in helping sweet itch sufferers. Omega 6 and 3 fatty acids are great for skin and flaxseed and evening primrose oils tend to be great sources of this. Additionally, spirulina can be a good addition as current research suggests it may be able to help to support healthy skin in sweet itch sufferers.

6. Ask about vet prescribed sweet itch medications

Depending on the severity of your horse’s sweet itch, your vet may recommend certain medications to help. Steroids are often given initially for either short or medium use to offer relief from skin irritation and itching, but these cannot be given long term as they can increase the risk of laminitis. Your vet may also prescribe antihistamines to help with symptoms but be aware that these will need to be given in high quantities and can be very expensive. Additionally, an anti-itch shampoo may be recommended to help reduce itching, this typically will need to be used regularly to help keep symptoms under control.

That’s our guide to sweet itch in horses and the current management methods. Looking for more horse care information? Check out our guide on rain scald in horses next.