Sweet Itch in horses: causes, treatment and prevention

Sweet itch, also known as Summer Seasonal Recurrent Dermatitis or Culicoides Hypersensitivity, is a prevalent skin condition in horses caused by allergic reactions to Culicoides midge saliva. The skin’s reaction results in intense and prolonged itching, causing hair loss, skin inflammation and open wounds, significantly impacting a horse’s comfort. It is essential for horse owners to understand its causes and management strategies to alleviate its effects and ensure their equine companions’ well-being.

Treating sweet itch may seem like a never-ending battle. Treating the condition early by commencing a suitable treatment programme is key to minimising the effect of this debilitating health concern for horses.

Here, we examine the cause, symptoms, diagnosis, treatment, and prevention of sweet itch to help you keep your horse comfortable and sweet-itch-free as the fly season draws closer!

Causes of sweet itch

Sweet itch is the most common allergic skin disease in horses, affecting around 5% of the UK’s population. The condition is caused by hypersensitivity to insects’ saliva, specifically of the Culicoides spp. type, which is more commonly known as mosquitos or midges.

The condition is often confused with other causes of skin irritation, such as mite and louse infestations. However, it typically affects horses over the age of 4, showing the progressive development of the condition’s severity with age. It also only becomes apparent from late spring to late autumn, with colder weather resulting in the absence of the symptoms.

What are sweet itch symptoms?

Symptoms of sweet itch include pruritus and severe itching of the skin. Signs to look out for include;

• Mild to severe rubbing of areas such as the back, mane and tail
• Broken hairs on the mane and tail
• Hair loss
• Dandruff
• Lumpy or scaly skin, which may be inflamed or hot to touch
• Areas of thickened skin
• Areas of sore or broken skin, which tend to bleed
• Weeping sores

Severe damage to the skin not only has long-term consequences, such as permanent loss of hair, damage to pigmentation, or permanently thickened skin, it may result in further complications. Open wounds predispose your horse to secondary infection and discomfort.

Additionally, the discomfort caused by sweet itch in horses may cause increased restlessness, resulting in weight loss. Therefore, it is important for owners to identify and control the problem appropriately for the horse’s overall health and well-being.

Diagnosis of sweet itch

Treatment of sweet itch should follow a confirmed diagnosis. Firstly, owners should identify the condition’s characteristics, which are seasonal in presentation and recurring year after year. Elimination of any other cause of skin irritation can also take place. Assessing the horse for mites and lice when grooming is one example. Also, consider that skin irritation can be a result of applying new products.

Diagnosis is confirmed through veterinary examination, which includes an intradermal skin test. This test involves injecting a small amount of the sweet itch cause, Cuiloides spp., within the layers of the skin to assess whether the horse is reactive.

Does sweet itch get worse?

Horses often start with a mild version of sweet itch at first, and as they grow older, it can get worse. The condition causes extreme discomfort and can have devastating effects on the horse’s well-being year on year.

The immune response to sweet itch will present itself season after season. Should your horse have suffered the year before, you should prepare the skin plenty in advance before the biting insect season approaches. You can also feed supplements year-round to help strengthen the skin’s structure.

Should your horse have suffered the year before, you should prepare the skin plenty in advance before the biting insect season approaches. You can also feed supplements year-round to help strengthen the skin’s structure.

Treatment – how do you get rid of sweet itch?

Treating sweet itch to rid your horse of the problem should start by combating the cause of the symptoms and offering relief from the intense itching sensation. There are a variety of products available; however, seeking professional help and treatment from your vet is advisable prior to application.

Your vet may prescribe steroids, which are often successful in eliminating sweet itch irritation insects cause. Steroids function as anti-inflammatory, reducing swelling and inflammation associated with irritation and, therefore, the itching sensation. It is recommended steroids be taken in the morning to produce the most effective results. They should only be taken during the season associated with sweet itch. Steroids are not suitable for horses affected by laminitis due to prolonged use being associated with the development of the condition.

Sweet itch cream

Soothing creams, shampoos, solutions, and sprays can also work to significant effect on sweet itch. Shampoos, such as Botanica’s Dilute Cleansing Wash, can provide instant relief from the itching sensation and are safe to use on broken skin and insect bites.

Shampooing the skin will also cleanse the hair of any potential allergens that may be irritating. Creams and solutions, such as the Botanica Anti-itch cream, can provide an extra layer of protection, reducing damage caused to skin from excessive rubbing through moisturisation and soothing the area. To read our full review on treatment products from Botanica, visit REVIEW Botanica, a Must for sweet itch sufferers.

There is a variety of other Sweet Itch Products for Your Horse’s Protection that when combined, can create an effective barrier to the problem starting, or getting worse.

Prevention of Sweet Itch

Prevention of sweet itch is more effective than treatment, fact. Early treatment using products from the Botanica range (application should ideally start mid-February) builds a barrier helping prevent the onset of the condition.

Although it may seem impossible, taking steps to reduce insect exposure can be extremely beneficial to the severity of sweet itch your horse experiences.

Stabling: When your horse in their stable, consider installing a mosquito screen to cover any doors or windows where mosquitos may gain access to your horse. Installing fans outside the stable can also be effective in helping reduce the fly burden. Although these measures may seem extreme, for some horses, even just a few mosquito bites can result in a major flare-up of symptoms and discomfort.

Turnout: Changes in turnout management will also decrease exposure to flies. The ideal turnout environment for horses suffering from sweet itch is open and windy, away from standing water and wooded areas where insects like to live and breed. Studies have suggested that insects are more active during sunset and sunrise, with little to no activity seen throughout the afternoon and night. Therefore, from late spring until late autumn, limited turnout around these times of the day.

Keeping paddocks clean, removing dung daily, and installing field fly traps may also assist in preventing the problem. Adequate shelter from the elements (sun, wind, and rain) should also be considered. Field shelters are excellent, but areas should be kept clean from dung to help prevent flies.

Studies have suggested that insects are more active during sunset and sunrise, with little to no activity seen throughout the afternoon and night. Therefore, from late spring until late autumn, turnout should be limited to avoid these times of the day.

Rugs and Repellents

The addition of a fly rug that offers complete cover may also be beneficial to your horse. An all over solution will provide a physical barrier to insect bites. Fly masks and add-ons, such as forelimb attachments, can aid in increasing coverage in extreme cases.

Fly repellents are essential when combatting insect attraction, alongside sweet itch. Use in conjunction with fly rugs and when stabled. Doubling up will provide maximum and the most efficient protection against any determined insect. Solutions containing citronella and benzyl benzoate can be effective for some horses and are widely available on the equestrian market. However, look out for fly repellents containing pyrethroids and Diethyl-m-toluamide (DEET), as these produce more potent effects.

Shampooing

Shampooing your horse regularly with soothing products and applying moisturising creams can be extremely beneficial in alleviating the persistent irritation and discomfort your horse is experiencing. Caution should be taken when skin is damaged, as horses can become extremely defensive and irritated when working close to the affected area. Choose a quiet time of day, take your time, and reward your horse for his cooperation.

Garlic

Garlic is hailed as an alternative herbal remedy for deterring flies. Interestingly, garlic oil could be a potential alternative to fly repellents. In humans, the application of a 1% dilution of garlic oil to the skin resulted in a 97% repellent effectiveness. However, garlic’s effect as an equine insect repellent is not proven. With the potential of toxicity from too much garlic, it may be best to stick with repellents for safe and effective pest control.

Supplements

All year-round supplements may help improve the structure and reaction of the skin from the fly bites. Invest in rugs, fly repelling sprays and lotions, and good time management instead.

The Take-Away

When tackling sweet itch, ensure you know what you’re dealing with by ruling out any other cause of skin irritation. Remember, symptoms should only be present between late spring and late autumn!

Precautions to reduce the effect of sweet itch include adaptation to general management to prevent insect bites and soothe already irritated skin. Schedule treatment programmes to begin mid-February. Keep up treatment throughout spring, summer, and early autumn.

Treatment programmes should begin mid-February, with regular reapplication throughout spring, summer and early autumn.

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