Sweet Itch in Horses: Causes, Symptoms, and Effective Solutions

What is sweet itch in horses?

In equine medicine, sweet itch is one of the most common allergic skin diseases in horses. The allergy to proteins in the saliva of various mosquito species is particularly common in Icelandic horses, but horses and ponies of all breeds can be affected. Mosquitoes are particularly active in the mornings and evenings from April to October, especially around bodies of water.

How does sweet itch develop in horses?

Sweet itch in horses is an allergic skin disease caused by an overreaction to proteins in the saliva of insects, especially black flies. These allergens trigger a strong immune response after an insect bite, leading to itching and inflamed areas of skin, particularly on the mane, tail, belly and head. Some horses, especially Icelandic horses and Shetland ponies, are genetically more susceptible. Exactly why this overreaction occurs in some horses and not in others is not yet fully understood. Environmental factors such as protein-rich pastures, stress and a weakened immune system can further exacerbate the symptoms of sweet itch.

A bite from a blackfly often leaves a red, swollen and very itchy area of skin. The itching can last for several days and the affected areas tend to become further inflamed due to constant rubbing. The bite of the blackfly is not only unpleasant for horses, but can also increase the risk of secondary infections if the skin is rubbed open.

How does sweet itch manifest itself in horses?

The first signs of sweet itch usually appear as a reaction to severe itching. As soon as visible chafing and thickening of the skin can be seen, the horse has usually already been bitten by mosquitoes. The following symptoms may indicate sweet itch:

• Skin rash in the form of pustules.
• Intense itching that leads to restlessness and frequent rubbing.
• Bald patches due to excessive scrubbing.
• Skin thickening and incrustations.
• Open and bloody skin areas and moist wounds.
• Secondary infections caused by bacteria or fungi that easily penetrate damaged skin.
• Papules (small lumps under the skin, often the size of a pinhead).

The constant rubbing exacerbates the skin damage and increases the risk of infection. In advanced stages, the skin may be thickened, dry and wrinkled, and the horse may lose a lot of coat. At this stage, the horse can often no longer be ridden.

Diagnosis and differentiation from other skin diseases

If these symptoms occur, a veterinary examination is essential. Sweet itch can easily be confused with other skin conditions caused by fungi, parasites such as mites, lice or hair lice or threadworm infections (Oxyuris equi). These conditions can cause similar symptoms, ranging from mild itching to severely sore areas of skin.

What helps against sweet itch in horses? 

What really helps against sweet itch varies from horse to horse. While one horse responds to conventional treatment methods, alternative treatment methods can provide relief for other horses. Find out below what treatment options are available and whether a sweet itch vaccination makes sense.

Treatment with conventional methods

The main aim of treating sweet itch is to alleviate the symptoms, as the horse will continue to rub if left untreated, which can lead to significant skin damage and secondary infections. At the beginning of a flare-up, vets often use glucocorticoids, which are administered either intravenously or intramuscularly. These drugs reduce the allergic immune response and quickly relieve the itching. In the further course of treatment, a switch is usually made to oral preparations.

Coat care plays a crucial role in the treatment. It is important to regularly remove dirt and incrustations with a saline solution. Zinc ointments can support the healing of inflamed and weeping skin areas. In the case of bacterial infections, antibiotic therapy is necessary and should be initiated by the vet. In addition, special shampoos can relieve itching, while aloe vera, both applied locally and mixed into the food, helps to heal the skin.

Recommended products for the treatment of sweet itch in horses:

• Aloe vera gel 99 % pure for skin and hair
• Saline solution 0.9 %
• Zinc ointment

Alternative treatment methods

Alternative healing methods are becoming increasingly important in the treatment of sweet itch. Many pet owners are opting for a holistic approach and often use homeopathic preparations such as sulphur, echinacea, ledum, staphisagria, graphites and cardiospermum. Schuessler salts are also used, for example Calcium phosphoricum D6 and Sodium chloratum D6 to treat dry eczema and Calcium fluoratum D12 for wounds, cracks and bark formation.

New vaccine technologies

The initial test results of an innovative vaccine technology are promising. Horses treated with the new vaccine against sweet itch showed good tolerance of the active ingredient and a reduction in tissue damage due to allergic reactions. In a study, Icelandic horses that are not affected by the allergy-causing midges in their home country were imported to Switzerland and treated with the new vaccine. These results give hope that the vaccination could protect horses worldwide from sweet itch in the future.

In addition, the active ingredient Insol, which is mainly used for fungal diseases, is seen as promising for improving the symptoms of sweet itch. Vaccination with Insol takes place before the insect flight season and is repeated two to three times. It is advisable to discuss with the vet whether vaccination with Insol is an option for the affected horse.

Protective measures and recommendations
Until the vaccines are widely available, it remains important to protect affected horses from the insects that cause the disease, adapt their feed and optimize their housing conditions. Horses suffering from sweet itch are often particularly sensitive, so their increased sensitivity should be taken into account. The good news is that the symptoms can be controlled with appropriate therapy and can reduce over time. However, early action at the first signs is crucial to ensure the horse's wellbeing.

Prevent sweet itch: 5 tips to avoid sweet itch in horses

The underlying disease, an allergy to components of mosquito saliva, cannot be cured. Nevertheless, various measures can make life easier for patients with sweet itch in summer. Here are five tips that can help you and your horse to avoid sweet itch.

1. optimize grazing time

It is crucial to minimize contact with biting midges as much as possible. The period from 10 a.m. to 4 p.m. is considered the phase when insects are least active and therefore the best grazing time for "eczema sufferers". Places near water, dung heaps and feed residues should be avoided and a retreat to an insect-free shelter or stable should always be possible. Sprays or lotions to repel insects are not equally effective everywhere and for every patient.

2. use eczema rugs

Eczema blankets offer reliable protection against the bites of female midges on sensitive skin areas. The blankets must fit well to prevent chafing, as only consistent use guarantees effective and long-lasting protection against the annoying pests. Many patients experience freedom from symptoms simply by wearing the blanket.

3. adapt feeding to eczema sufferers

Although the feed industry provides a wide range of preparations for "eczema sufferers", sweet itch unfortunately cannot be cured by supplementary feed. However, the supply of minerals and trace elements should be checked and optimized, especially for patients with skin diseases. Many patients show an improvement in symptoms by reducing starch and protein-rich feed. A fundamental review of the feed ration is therefore an important part of the therapy in order to achieve symptom relief through improved metabolic function. Find out more about the correct feeding of horses.

4. use insect repellent products:

There are numerous products on the market that can be applied locally. They are designed to care for the affected areas of skin, protect against insects and contribute to healing. Here too, not every product helps every "eczema sufferer" in the same way. It is often necessary to try out different products and some manufacturers therefore offer trial packs. Hygiene is crucial for local treatment. Residues of care products should be washed off at least once a week with a mild shampoo to give the skin time to dry. It is essential to wear disposable gloves when applying the care products to avoid constant skin contact with the product and the diseased skin.

5. consider the location of the barn and pasture

In the USEF Learning Center powered by ClipMyHorse.TV explains Hope Hobday Glynn what measures can be taken to reduce the occurrence of insects near stables. The American explains how this can be done in just a few simple steps in the following video:

To minimize the risk of sweet itch in horses, choosing the right stable location plays a decisive role. Horses prone to sweet itch should not be kept near bodies of water, manure heaps or leftover feed, as these attract insects, especially midges. Such places provide ideal breeding grounds for midges, which can promote the outbreak of eczema. A hutch with insect screens on the doors can also help to keep the insects away. Shady areas, such as hedges or trees, should also offer the horse places to retreat to during the day. An open stable or an insect-free shelter also offers important protection against insect bites, especially during times of increased insect activity such as mornings and evenings.

Sweet itch in horses: Summarized

Sweet itch is a challenging skin condition that can severely affect a horse's well-being. Early recognition of symptoms and targeted treatment are crucial to relieve itching and prevent serious skin damage. Both conventional and alternative treatments can help to control the symptoms and improve the horse's quality of life. There is currently no widely available vaccine for sweet itch, but promising developments in research give hope for future progress.

Until then, it remains important to take protective measures against insect bites, optimize feeding and husbandry conditions and pursue individually tailored care and treatment strategies. With a comprehensive approach and the right care, the symptoms of sweet itch can be successfully managed and the well-being of the affected horse ensured.‍

Sweet itch in horses: The most important questions and answers

What is an eczema horse?

An eczema horse is a horse that suffers from sweet itch, an allergic skin disease caused by the bites of certain types of mosquitoes, particularly Culicoides mosquitoes. This allergy leads to severe itching and skin damage as the horse rubs excessively.

When is a horse an eczema sufferer?

A horse is considered to have sweet itch if it shows symptoms of sweet itch over a long period of time, such as severe itching, rashes, crusting and hair loss. The diagnosis should always be made by a vet in order to rule out other skin diseases.

How can I relieve my horse's itching?

Special shampoos, aloe vera gel or healing ointments can be used to relieve itching. Glucocorticoids, which are prescribed by the vet, can also reduce itching. Regular cleaning of the affected areas of skin and avoiding insect bites are also important.

Is there a vaccination against sweet itch?

There is currently no officially approved vaccine against sweet itch, but initial test results of an innovative vaccine technology are promising. Research is ongoing and a market launch could take place in the next few years.

When is the vaccination against sweet itch coming?

It is difficult to give an exact date as the vaccines are still under development. Initial studies are promising, but it may be several years before a vaccine is generally available.

What to do if the horse has eczema?

If your horse has been diagnosed with eczema, you should take measures to reduce mosquito bites, e.g. by using insect repellents and fly rugs. Specific coat care, skin care and a special diet can also help. In severe cases, veterinary treatment with medication is necessary.

Which feed is suitable for horses with eczema?

A balanced diet with high-quality, preferably natural ingredients is recommended for horses with eczema. Feed rich in omega-3 fatty acids can have an anti-inflammatory effect. Feedstuffs rich in sugar or starch should not be fed. A muesli for horses with eczema should contain little sugar and starch and be rich in omega-3 fatty acids. There are special feed mixtures on the market that are designed for sensitive horses. If in doubt, seek advice from an expert or vet.

Which feed helps eczema horses to gain weight?

In order to feed an underweight horse with eczema a healthy diet, the feed should contain a high proportion of easily digestible fiber and high-quality fats. Feed with a moderate energy content, low in sugar and starch, but rich in healthy oils, such as linseed oil, is suitable.

Is garlic good for horses with sweet itch?

The effectiveness of garlic against sweet itch is controversial. While some horse owners report that garlic acts as a natural repellent against insects, it can cause stomach problems in other horses. Feeding garlic should therefore be done carefully and in consultation with a vet.

Can sweet itch in horses be cured?

As a rule, sweet itch cannot be completely cured, but the symptoms can be significantly alleviated and controlled with appropriate treatment and care. Early measures and consistent therapy can help to positively influence the course of the disease.