Sweet itch in horses

Allergic summer eczema is an annually recurring dermatosis ( skin disease ) in horses in the warm season. It can be attributed to insects’ sweet itch in horses ( especially biting midges ).

Identify summer eczema symptoms in horses and prevent triggers.

When the warm, balmy summer evenings invite you to take a well-deserved ride out into nature, many riders are surprised by his unusually nervous horse. It is not uncommon for the ride to end prematurely, and there can be no question of recovery for either side. This usually happens when riding in the morning or at dusk, preferably on bodies of water, rivers, or on the edges of forests or dunghills.

This is where the midges and black flies are primarily found – the triggers for the symptoms of summer eczema in horses. You can primarily recognize eczema by restlessness and severe itching, which can spread from the horse’s head, through the mane, to the tail. However, these signs of summer eczema are also typical of other skin diseases, such as biting lice and mange.

The cause of summer sickness in horses is the sensitization of horses to a specific protein in mosquito saliva. What is still controversial is what exactly leads to this allergy before it is triggered for the first time. Therefore, it is particularly important to recognize the symptoms in good time to prevent the suffering of eczema as quickly as possible.

The diagnosis of summer eczema is a great shock for many horse owners because a judgment of the Flensburg district court states that the reduction in the use of eczema is 50 – 100% of the value. Sweet itch also means great suffering for the horse itself, which often receives much of our love. A blood test usually makes the diagnosis.

Many horse owners are all the more interested in how they can recognize the symptoms to prevent them effectively. The basic prerequisite for this is to understand the triggers and causes of eczema that has broken out and, if possible, to avoid them as best you can.

Symptoms of sweet itch in horses

The sweet itch symptoms that are the first to be recognized in horses are mostly the result of the itching that has been triggered. So by the time you see the familiar chafing and thickening of the skin, eczema has already been bitten by Culicoides mosquitoes. If the following signs are discovered, rapid Prevention is the focus:

Recognizing the change to eczema in good time

First, the mosquito bite manifests itself in a painless skin rash, which appears immediately after the insect bite. In summer, therefore, after every ride – even when kept in an open stable or when grazing – watch out for small bumps, primarily in areas with vertical hair, i.e., the tail, mane crest and abdominal seam. This is usually followed by itching after a few hours.

If no skin rash can be seen, but the horse rubs heavily in these areas and is restless, this is a clear warning signal. Other areas of the horse may also be affected, most likely depending on the mosquito species. Experience has shown that the symptoms of eczema develop between the ages of 3 and 6.

Other symptoms – hair loss and weeping spots

Lumps may form under the skin, usually only the size of a pinhead, called blemishes. The horse rubs itself constantly, and the resulting bare, open skin harbors the risk of a secondary infection. Bacteria and fungi can also easily penetrate weeping or bloody wounds. By this point, the condition had already worsened. An unsightly cycle begins, which entails an increasing impairment of the general condition and wound healing. Depending on the spread of eczema, a horse is (then) no longer rideable.

When the disease breaks out, a confirmed veterinary diagnosis is essential, as other skin diseases caused by fungi and parasites such as mites, lice and biting lice or an infection with the roundworm ( Oxyuris Equi = causes symptoms ranging from slight tail chafing to chafed buttocks enough) similar symptoms can arise. The skin often appears thickened, wrinkled, and dry in a chronic course. Another feature is hair loss.

Culicoides mosquito bites as triggers of Sweet itch in horses

The culprits are mostly the Culicoides mosquitoes ( midges ) and sometimes the black flies ( Simulium ), but other insects such as horse flies can also trigger sweet itch symptoms. Only the fertilized female mosquitoes pose a threat. As they bite, their saliva gets into the skin, which contains a protein to which sensitized horses are allergic.

In the case of an allergy sufferer, corresponding antibodies are formed upon initial contact with the mosquitoes, resulting in the release of certain messenger substances ( histamine ). So most of the time, the symptoms start with the mosquito season, between April and October every year.

During these months, the mosquitoes swarm, especially near bodies of water, and bite the horses at dusk.

Many riders are already familiar with the term summer mange in this context. An infestation causes summer mange with mites, not by black flies or biting midges like summer eczema.

Other causes of sweet itch in horses

The actual cause lies in the sensitization of the horses, which leads to an allergy, which is triggered again every summer if the trigger (mosquitoes) is not combated or at least kept away from the horse. However, what exactly causes the sensitization is currently controversial. However, there are probably many factors that increase the risk of developing eczema. However, a weakened immune system is considered to be partly responsible.

Nutrition, habitat, condition, and stress level of the horse also influences the development of sensitization to the saliva of the mosquito species Culicoides. Metabolic disorders and malnutrition also promote this clinical picture.

Experts also name the following causes:

• Too much grazing on energy- and protein-rich meadows.
• Lack of exercise.
• Problems with bowel function.
• Too much starch and carbohydrates.

Itching is largely responsible for the course of Sweet itch in horses disease.

Because the bite of the black fly leads to an immediate reaction of the skin, mostly in the form of an oedematous inflammation, which causes severe itching in the horse, it is this itching that is responsible for the classic symptomatic appearance and course of the sweet itch. From now on, the horse will chafe, which leads to more and more wounds and damaged skin. Sometimes horses even rub themselves bloody. The skin thickens, and the typical wavy crest of the mane develops. This affects the elasticity and can lead to tears, for example, when eczema lowers its head to eat. Secondary infections can also occur as the animal rubs other pathogens almost into the open wounds when it rubs itself.

Prevent sweet itch

However, you can influence the intensity and frequency of the itching and the health consequences and thus reduce the suffering of eczema. But proper Prevention of sweet itch symptoms requires discipline and continuity. Equally important is balanced and needs-based horse feeding.

As a precaution, care products and repellents ( fly spray ) are used in connection with eczema blankets.

Veterinarian Lisa Butterweck adds: “Prevention covers a wide spectrum. There are two goals”:

• Avoid contact with the insects.
• The relief of clinical symptoms.

The main recommendation for preventing summer eczema in horses is to keep the insects away as far as possible and care for the skin and support the regeneration of the coat and the chafed horse skin. You should also avoid mosquito hotspots, especially in the morning and at dusk, and protect your horse from bites with an eczema blanket or repellents when grazing and riding.

Avoid mosquito hotspots as a preventive measure:

• Around streams and ponds.
• Near dung heaps.
• At forest edges.

Remove dander and care for the horse’s coat.

For gentle care of the sensitive horse skin and coat, to stimulate the regeneration of mane and coat and to relieve itching, we recommend using our remedy for sweet itch and lice on horses.

This cortisone-free combination of nourishing oils and other ingredients gently removes dandruff and encrustations so that you can easily remove them later with the help of a comb. After a short time, the itching is noticeably relieved, and the vicious circle of open wounds, secondary infections and even more itching is broken. The smell is pleasantly lemony, and horse owners report that the mosquitoes hold back at first. Should start the application at the beginning of the mosquito season to prevent further skin irritation.

Depending on the progression and tolerance of the horse, eczema blankets with head protection have also proven their worth. Low-protein feeding is also recommended and, if necessary, the administration of additional food. To enable the horse to be kept appropriately to the species despite all the circumstances, you should know that the mosquitoes prefer a windless, warm, and humid environment and the vicinity of dung heaps and water bodies. They are also most active at dawn, dusk, and night. Therefore, it is advisable to adopt the grazing time accordingly to stabilize the horses overnight and keep the paddock and paddock areas as clean as possible.

Treatment and care of sweet itch in horses

Tips and experiences of our vet Lisa Butterweck: Treatment and care of horses with sweet itch ( Culicoides hypersensitivity, sweet itch )

Allergic summer eczema is an annually recurring dermatosis ( skin disease ) in horses in the warm season and can be attributed to sensitization by insects (especially biting midges). There is no such thing as a complete and universal treatment and care because every horse responds differently to the different care products, shows different levels of symptoms and reacts differently to the different therapeutic approaches. However, there are elementary components in the care of eczema and its predominant symptoms: scaly skin and itching, especially on the tail and mane crest. In any case, should treat these ailments with care, and the corresponding areas should be cared for to relieve the itching. This reduces the risk of secondary infections and the suffering of eczema. If the following tips from the veterinarian on how to deal with eczema are observed, a horse should be able to lead a mostly happy life despite the allergy.

Main ingredients of sweet itch treatment

One bite from the Culicoides mosquito is enough for the allergic reaction of eczema to start again – summer after summer. The most noticeable symptom is the severe itching (from April to October) on the mane, tail root, and belly seam. Must treat it in any case, also to prevent secondary bacterial infections because a horse often rubs and scratches so intensively that open and bleeding wounds, incrustations, and flaking occur. As a rule, the symptoms disappear completely in winter. It is a type IV and type I contact allergy. The saliva of the female insects is responsible for the sensitization or the protein it contains. The diagnosis of the sweet itch is usually based on the clinical picture but can be confirmed by an allergy test or blood test.

Sweet itch treatment covers a wide spectrum. There are 2 important goals:

• Prevent contact with insects (e.g., with an eczema blanket)
• The relief of the clinical symptoms (itching, restlessness, open wounds).

Because the summer eczema in the horse itself, or the actual cause, cannot simply be treated like this. Rather, the treatment aims to prevent the symptoms from being triggered and relieve the itching and support the regeneration of the skin and coat. Otherwise, eczema will keep scratching until open sores appear and the skin becomes sore. This, in turn, promotes secondary infections since an attacked and partially open skin opens the door to other pathogens. Careful grooming and treatment of the symptoms break this vicious circle and strengthen the horse’s coat and immune system in the long term.

Prevent contact between insects and eczema

One treatment option is to keep the insects away from the affected eczema to prevent the allergic reaction and associated itching from being triggered. This is possible, for example, by changing the location, changing the grazing time (stalling the horses at dawn and dusk), or daily treatment with repellents ( fly spray ).

However, this is only an option for horses whose symptoms are minor. In addition, it is advisable to avoid the following things and places:

• Bodies of water, rivers, and forest edges (a hotspot for mosquitoes).
• For mosquitoes, horseback riding, and open stables at peak times (dawn and dusk).
• The dung heap is also popular with mosquitoes.

The article about insect protection for horses in our blog is also interesting.

Treatment with the active ingredient deltamethrin (applied as a spot-on every 10 to 14 days) or permethrin (applied to the coat every 14 days) is also possible. However, these active ingredients are also repellents and do not have to be applied daily. The so-called eczema blankets are also often used. These usually cover the horse completely so that the mosquito no longer has the opportunity to bite and thus transfer its saliva, which causes itching. In some horses, the fungal vaccination (twice at intervals of 14 days) is helpful. However, the exact mechanism of action for summer eczema is not known.

Care of the clinical symptoms (itching, scratched skin)

Glucocorticoids ( cortisone ) have a symptomatic effect but relieve the itching of affected horses very quickly. It is best to start with parenteral administration (e.g., intravenous or muscular injection of betamethasone or methylprednisolone ). Can make a switch to oral administration ( e.g., prednisolone ).

The care of irritated and sensitive skin and fur has proven to accompany therapy. In the case of heavy soiling, crusting, and sticking of the hair, a cleaning, including hair removal, must be carried out first. Physiological saline solution is better used for this than water. For sensitive and weeping areas, oily preparations of zinc oxide are the means of choice, with bacterial involvement, disinfecting ointments or emulsions. Local treatment depends on the character of the inflammatory change.

Causal treatment of sweet itch by allergy vaccination

The cause is treated, i.e., the overreaction of the immune system. For this purpose, blood is drawn from the horse, and an allergy test is carried out. The horse must be free of cortisone for at least 6 weeks. The test determines which insects (e.g., midges, black flies, horseflies, etc.) the horse is allergic to. With the help of these results, an injection solution is prepared that contains the required allergens. This solution is injected under the skin once a week at the beginning and later every 2 to 4 weeks. The owner usually does this himself according to the instructions. Through hyposensitization ( allergy vaccination), the immune system is supplied with an ever-increasing amount of the allergen. The aim is to get used to the allergen to prevent the immune system from overreacting. The success of the therapy is the reduction of the symptoms. In some cases, they no longer occur. However, they must carry out life therapy.

With eczema blankets against black fly bites and itching in eczema

Black fly bites can cause extreme itching, chafed skin and open, weeping wounds in horses. No wonder because they are the triggers of summer eczema. A protein in the mosquito’s saliva triggers an allergic reaction to eczema. The constant itching, particularly noticeable in the mane and tail region, is very stressful for the animal, and chafing can lead to further infections. This, in turn, attracts even more black flies or midges. Therefore, the aim is to prevent blackfly bites from allowing the horse’s skin and coat to regenerate. And that is only possible with relieving itching.

An eczema blanket can help here because it can prevent new bites and thus relieve the itching. Without such a blanket, skin infections caused by the horse’s itching and chafing would only worsen. In healthy animals, the eczema blanket ensures that being bitten is significantly reduced during the mosquito season.

What is an eczema blanket?

An eczema rug, also known as a fly rug, is a particularly fine-meshed rug with a high level of breathability to protect the horse’s diseased skin and prevent further skin inflammation and insect bites. These blankets are divided into two versions and are preferably used in the disease of summer eczema. As the name suggests, this clinical picture has its high season in summer, and the blanket should be breathable so that the horse does not suffer from heat build-up even in the warm summer months. At the same time, the sensitive skin areas, in particular, are protected from direct sunlight.

In allergy sufferers, summer eczema is caused by insect bites, primarily those of the black fly. And to successfully keep them away, the ceiling must be correspondingly fine-meshed. Horses that suffer from severe itching sometimes chafe themselves constantly. Therefore, the eczema blanket must be sturdy enough to withstand it.

The wearing time of an eczema blanket depends on the horse’s tolerance and should be adjusted accordingly to prevent summer eczema effectively.

What properties should the eczema blanket have?

A rough distinction is made between the two versions. One form of the eczema blanket is similar to the usual blanket cut, either with an integrated neck part or this is removable. The other type of blanket is put over the horse’s head. This form is often used when the sweet itch is severe. Depending on the model, there are other fixations, for example, on the hind legs or so-called cross straps.

Skin areas particularly affected by summer eczema are the mane and tail region and the abdominal seam, i.e., areas with vertical hairs. The eczema blanket should, of course, provide particularly good protection in these areas and should cover the mane region completely with the neckpiece. However, this neck part should not be too short so that the horse remains almost undisturbed when grazing. In addition, the tail flap should generously cover the root of the tail. In addition, blankets with a belly flap are recommended for horse riding to protect against mosquitoes.

There are different recommendations for determining the correct ceiling size depending on the manufacturer. In addition to a too large rug, a too-small rug also poses a risk to the horse in the form of additional chafing of the already sore or sensitive skin. A quick-drying material is an advantage in the warm summer months, and warm summer rain is just as acceptable. Otherwise, there are already fly rugs with an integrated rain cover protecting the sensitive back and kidney area from wetness and cold.

Which factors can promote an overreaction of the immune system?

Sweet itch in horses are Allergic summer eczema – an excessive immune reaction, in this case in the form of an allergy with corresponding skin symptoms.

Nutrition specialists keep pointing out the right diet for eczema. Needs-based feeding is recommended. If necessary, this includes limiting the grazing time, adapted amounts about the movement of the animal, and an adequate supply of all necessary vitamins, minerals, and trace elements—the most important organ for an intact immune system in the intestine. Since the feeding can have a direct effect here, so to speak, a check and a possible change of feed is at least another point in the holistic view of the treatment of summer eczema and should be considered in addition to the symptomatic treatment.

Experts recommend avoiding

• Ensiled feed (haylage).
• Long roughage breaks.
• Large doses of concentrated feed.
• A concentrated feed with structure.
• Feeding foods high in sugar and pectin such as carrots, apples, bananas, treats, and bread.
• For imported horses, feedstuffs do not correspond to their home countries.