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Recurring Horse Rashes: Common Causes and Treatment

Last updated: December 5, 2023

By: Miles HenryFact Checked

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If the mere thought of creepy crawly mites, sweet itch, and rain rot makes your skin crawl, imagine what it would be like if you didn’t have hands to scratch. If you’ve noticed that your horse keeps getting a rash, you’re probably wondering what could be causing it and how to prevent it from happening again.

Horse rashes can be caused by various factors, including allergies, infections, environmental conditions, poor hygiene, and nutritional imbalances. Treatment of horse rashes depends on the underlying cause. Allergic reactions may be treated with antihistamines or corticosteroids, while fungal or bacterial infections may require the use of antifungal or antibiotic medications.

In this article, we’ll explore some of the common causes of recurring rashes in horses and discuss some treatment options that may help prevent them from happening again. If you’re concerned about your horse’s health, it’s always a good idea to consult with a veterinarian who can help you identify the cause of the rash and recommend the most appropriate treatment plan.

Why Does My Horse Keep Getting A Rash?

It can be frustrating and concerning if your horse keeps getting a rash. A variety of factors, including allergies, insect bites, fungal or bacterial infections, and environmental irritants such as grasses or plants, can cause rashes.

The horse pictured above was one of three that came down with a rash. We had the vet check the horses, and he said he has seen this in a number of horses in our area, and it’s a fungal infection.

It is important to identify the underlying cause of the rash in order to treat it properly and prevent future outbreaks. In this section, we will explore some of the common types of recurrent horse rashes and how to identify them.

A picture of our filly with a type of horse rash.
Recurring rash

Common Equine Rashes And How They Appear

Most horses get rashes of one kind or another in their lives. As mentioned, the itchy rash is only a symptom of something else that is going on, and there is any number of possible causes. However, some are more common than others, and I’ve listed eight common reasons horses get rashes.

ConditionWhat It Looks Like
Sweet Itch / Hives / Summer itchItchy hives or welts erupt on affected parts of the body. They may appear as circular bumps or target-like raised lesions.
MangeA rare condition in horses and mainly affects elderly animals or those in poor condition. There are several types of mange which are all uncomfortable. Symptoms include inflammation, hair loss, and excessive itching.
Rain Rot / Rain scaldA distinctive, crusty, weepy layer of scabs that mainly occurs on the horse’s topline or face. Patches of hair may fall out.
LiceCharacterized by rubbing, itching, and discomfort, which results in patches of matted hair or hair loss. (Horse lice and human lice are not the same, so owners rarely need to worry about them spreading to themselves)
Allergic DermatitisA rash can break out on one part of the animal’s body or be in multiple places. It can take various forms – rash, hives, welts. Causes can vary, so diagnosis usually requires some detective work.
Parasites, including ticksTicks and mites – Manes, tails, inside legs, ears, these nasty parasites are masters at hiding and have no mercy. Bites become itchy and, if scratched, can quickly turn into rash-like skin conditions characterized by scaly, weepy sores.
Mud rash / Mud fever / greasy heelSwelling, hair loss, sores, scabs discharge around the lower limbs – most common in wet seasons.
RingwormScaly, weepy, red, round, itchy patches. Hair may fall out in small clumps.

Treatment for horse rashes depends on the underlying cause of the rash. In some cases, the rash may resolve on its own with proper care and hygiene, while treatment with medications or other therapies may be necessary for others.

Unless the cause of a horse’s rash is apparent, no advice or remedy should take the place of a consultation with a veterinarian. Prompt and appropriate treatment can help prevent the rash from becoming more severe or spreading to other areas of the body.

Sometimes, the only way to treat a niggling rash is to take a skin scraping to identify the offending organism so treatment can be targeted. Understanding the root cause of your horse’s rash can help you take steps to prevent future outbreaks and ensure the health and well-being of your horse.

Equine skin rashes can be frustrating. Sometimes, the more you try to treat the condition, the worse it seems to get. While there is no replacement for professional diagnosis, let’s go through some common causes of horse rashes.

Possible Causes Of Horse Rashes

Although skin rashes can manifest on different parts of the horse and vary in appearance, you can be sure of one thing. They are all itchy and must be dealt with to avoid spreading and causing further discomfort.

While some horse rashes have known causes, others, like allergic dermatitis, could be caused by any number of things. Like humans with allergies, some horses may be allergic to something like fly spray, something in their food, or a plant in their paddock.

Understanding the cause of each condition can go a long way in the treatment and prevention of further outbreaks. The most common causes of skin rashes are:

BacterialRain rot and mud fever
FungalConditions like ringworm
ParasiticMange, lice, ticks, etc.
AllergiesSweet itch (surprisingly, the raised lumps are not caused by the insect bites themselves, but rather by the horse’s immune system that goes into overdrive as an allergic reaction to the insect’s saliva).   Environmental allergies (for example, dusty hay or reaction to wood shavings used for bedding).   Contact allergies (like your horse shampoo or sprays).   Food allergies (even carrots or apples could be the cause for some individuals).  

Allergic reactions

Allergic reactions can be a common cause of horse rashes. Horses can develop allergies to different substances, including insect bites, certain plants, and certain feed ingredients. When a horse comes into contact with an allergen, the immune system overreacts, leading to inflammation and irritation of the skin. This can cause a rash to develop.

Allergic reactions can range in severity from mild skin irritation to more severe reactions such as hives or anaphylaxis. Allergic reactions can be triggered by a variety of substances, including:

  • Insect bites: Flies, mosquitoes, and ticks can all cause allergic reactions in some horses.
  • Certain plants: Some plants, such as poison ivy or oak, can cause allergic reactions in horses when they come into contact with the plant or its pollen.
  • Feed ingredients: Horses can also develop allergies to certain feed ingredients, such as corn or soy.

If you suspect your horse may be experiencing an allergic reaction, it is essential to consult a veterinarian for proper diagnosis and treatment. Treatment may involve using antihistamines or corticosteroids to manage the allergic reaction and reduce inflammation. Avoiding exposure to known allergens can also help to prevent future allergic reactions and rashes.

Below is a helpful YouTube video that explains allergic reactions in horses.

Insect bites

Insect bites can be a common cause of horse rashes. Varied insects, including horseflies, mites, mosquitoes, and ticks, can bite horses. These bites can cause inflammation and irritation of the skin, leading to the development of a rash.

Flies are a common problem for horses, especially during the warmer months. Flies can cause irritation and discomfort for horses, leading to excessive scratching and rubbing, resulting in skin irritation and rash. Mosquitoes and ticks can also cause skin irritation and rash in horses. But the worst of all for my horses are mites.

Mites are small, eight-legged parasites that can infest the skin of horses and cause irritation and rash. Several types of mites that can affect horses, including:

  1. Scabies mites: Scabies mites, also known as sarcoptic mange mites, can infest the skin of horses and cause a condition known as scabies or sarcoptic mange. Scabies mites burrow into the skin and lay eggs, leading to intense itching and the development of a rash. These are rare.
  2. Chorioptic mites: Chorioptic mites are a type of mite that can infest the lower legs and hooves of horses. These mites can cause inflammation and irritation of the skin, leading to the development of a rash. These are common.
  3. Demodex mites: Demodex mites are a type of mite that can infest the skin of horses and cause a condition known as demodicosis or “red mange.” Demodex mites burrow into the skin and lay eggs, leading to irritation and the development of a rash. These are rare.

In addition to causing discomfort and irritation, insect bites can also transmit diseases. Ticks, for example, can transmit Lyme disease and other infections. It is essential to take steps to prevent insect bites and protect your horse from these pests.

Using insect repellents like a good horsefly spray and keeping the horse’s environment clean and free of standing water can help to reduce the risk of insect bites. If your horse has a rash that you suspect may be caused by insect bites, it is important to consult with a veterinarian for proper diagnosis and treatment.

Picture of a rash in a horse's ear.
Rash in a horse’s ear

Fungal or Bacterial Infections

Fungal or bacterial infections can cause skin irritation and rash in horses. These infections can be caused by contact with contaminated soil or water or by coming into contact with an infected animal.

Various fungi, including dermatophytes, yeasts, and molds, can cause fungal infections, and numerous bacteria, including staphylococcus and streptococcus, can cause bacterial infections.

Symptoms of fungal or bacterial infections in horses can include skin irritation and redness, swelling, itching, and hair loss. These infections can be uncomfortable for the horse and may cause them to scratch or rub the affected area, leading to further irritation and inflammation.

If you suspect your horse has a fungal or bacterial infection, it is important to consult a veterinarian for proper diagnosis and treatment. Treatment may involve using antifungal or antibiotic medications to kill the infection and manage the rash.

It is also important to keep the horse’s environment clean and free of contaminants to prevent the spread of infection.

A picture of a yearling with a horse rash on its face.

Environmental irritants

Grasses and plants can contain chemicals or substances that can cause irritation to the skin of horses. Some plants, such as poison ivy or oak, can cause allergic reactions in horses when they come into contact with the plant or its pollen.

Other plants, such as nettles or thistles, can cause irritation and rash when they come into contact with the skin. Environmental irritants can also include chemicals and substances found in the horse’s environment.

For example, certain cleaning products or insecticides may cause irritation to the skin of horses. If you suspect an environmental irritant is causing your horse’s rash, it is important to identify and keep it away from your horse.

Avoiding exposure to known irritants can also help prevent future rash outbreaks. If the rash is severe or persists, consult with a veterinarian.

Nutritional imbalances

A horse’s diet plays a crucial role in maintaining the health and well-being of its skin. An inadequate or unbalanced diet can lead to deficiencies or excesses of certain nutrients, which can affect the health of the skin.

For example, a deficiency in essential fatty acids can cause dry, flaky skin and may contribute to the development of rashes. An excess of certain minerals, such as copper or zinc, can also cause skin problems in horses.

It is important to ensure that your horse’s diet is balanced and provides all of the necessary nutrients for optimal health. Consult with a veterinarian or equine nutritionist to determine the appropriate diet for your horse. Regular grooming and bathing can help maintain healthy skin and prevent skin problems.

Picture of a horse with a rash in its ears.
Olivia clearing up from her rash.

Poor Hygiene

Poor hygiene can contribute to the development of skin problems in horses, including rashes. Horses are prone to various skin conditions, and maintaining good hygiene practices can help prevent these conditions from developing.

Some factors that can contribute to poor hygiene in horses include:

  1. Infrequent grooming: Regular grooming helps to remove dirt, sweat, and other contaminants from the horse’s coat and skin. Neglecting to groom a horse regularly can lead to the build-up of dirt and bacteria on the skin, which can cause irritation and rash.
  2. Infrequent bathing: Bathing a horse regularly helps to keep the skin clean and healthy. Neglecting to bathe a horse can lead to the build-up of dirt and sweat on the skin, which can cause irritation and rash.
  3. Poorly-maintained bedding: Bedding that is dirty or wet can cause irritation and rash on a horse’s skin. Keeping the horse’s bedding clean and dry is important to prevent skin problems.
  4. Lack of access to clean water: Access to clean, fresh water is important for maintaining the health of a horse’s skin. Neglecting to provide a horse with clean water can lead to dehydration and skin problems.

Maintaining good hygiene practices can help to prevent skin problems and keep your horse’s skin healthy. Regular grooming, bathing, and maintaining clean bedding and water sources can all contribute to the health and well-being of your horse.

If your horse has a rash that you suspect may be caused by poor hygiene, it is important to address any hygiene issues and consult with a veterinarian for proper diagnosis and treatment.

What causes hives on horses?

Hives, also known as urticaria, are a type of skin rash that can occur in horses. Hives are characterized by the appearance of raised, red welts on the skin that may be itchy or painful. There are several potential causes of hives in horses, including:

  1. Allergies: Hives can be caused by allergies to things such as insect bites, certain medications, or certain types of food.
  2. Infections: Bacterial or viral infections can sometimes cause hives in horses.
  3. Physical irritation: Hives can be caused by physical irritation of the skin, such as from friction or rubbing against a rough surface.
  4. Toxic substances: Exposure to certain toxic substances, such as certain plants or chemicals, can cause hives in horses.
  5. Stress: Hives can sometimes be triggered by stress in horses.

It’s essential to identify the cause of hives in order to properly treat the rash. Your veterinarian will be able to help you determine the cause and provide appropriate treatment.

Potential Causes And Treatment Plans

Treatment of equine skin rashes is dependent on accurate diagnosis. Using a medicated wash on a horse that is allergic to an ingredient could make the rash a lot worse. Before adding fuel to the flames, make sure you have pinpointed the condition and used the appropriate treatment.

While many rashes in horses will require veterinary intervention, issues like ringworm and mange can be treated with topical washes and ointments. Eliminating causes for the condition, like dampness or parasites, is also an essential part of treatment, or the rash cycle will never fully be broken.

Relieving the itch factor should also be of utmost importance when treating rashes. While the itch itself is only a symptom, a horse that is constantly rubbing, scrubbing, and biting its skin to relieve dermal irritation is highly likely to end up with a secondary infection.

Soothing medicated shampoos or topical creams can alleviate surface itching in some conditions and can go a long way to prevent further skin damage. In addition to treating the cause of the skin rash, when allergies cause the condition, antihistamine medication may be useful to help relieve symptoms.

Tips For Owners To Prevent Equine Skin Rashes

While no one is more qualified than a veterinarian to diagnose and treat rashes, no one knows a horse better than its owner. You know which funny characters enjoy standing for hours in the muddy creek or sticking their heads into every thicket in the yard.

By remaining aware of factors that may result in skin rashes, owners can be well prepared to tackle conditions head-on the moment they appear. Some tips for owners include:

  • Early intervention – Fungal and bacterial rashes are highly likely to spread if they aren’t treated quickly. That makes early detection and intervention the best weapon to combat unsightly, uncomfortable skin conditions. Regular grooming isn’t about keeping the horse brushed and shiny – it is also an opportunity for owners to check their animals and note any skin irregularities.
  • Keep environmental causes in mind – If you expect periods of heavy rain, it may be a good idea to limit the hours your horse spends outside – rain rot and mud fever are often directly related to wet conditions. Also, keep their bedding clean and dry.
  • Have your anti-rash ammunition on standby – Summer itch can be prevented or limited to a large extent by using insect repellents or adding a fly sheet. In addition, keep some veterinary-prescribed antihistamines on hand if you have a horse that struggles with this common skin condition.
  • Keep a rash diary – One of the best tips to prevent skin rashes is to keep a daily diary of your horse’s routine. You may find your horse gets a rash every weekend after the neighbor’s kids visit with bags of special snacks. This may sound tedious, but it is amazing how small, seemingly insignificant factors may cause your poor pony’s itchy, scratchy skin condition.

List everything, including diet (plus treats), weather conditions, sprays, and your horse’s activities. After a few weeks, you may start noticing some patterns, which can eliminate a lot of the guesswork and hopefully some of the expense of treating recurrent, unpleasant rashes.

I’ve tried every home remedy recommended to me to get rid of various types of rashes. Most were ineffective, but one worked. This will sound silly, but I rubbed banana peels in my horse’s ears to eliminate rashes caused by mites.


Accurate diagnosis is an essential step in the treatment and future prevention of equine skin rashes. Itchy skin is not a condition in itself; it is only a symptom. Rashes can result from bacterial, fungal, or parasitic causes. It may also be because of an allergic reaction to an environmental factor, diet, equine product, or medication.