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12 Most Common Horse Diseases and Ailments

12 Most Common Horse Diseases and Ailments

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Despite our best efforts, all horses will contract some sort of ailment or disease during their lifetime.

Having a good understanding of the most common horse diseases and ailments is essential for making sure our horses stay healthy for as long as possible.

The most common horse diseases and ailments are colic, laminitis, gastric ulcer syndrome, arthritis, and equine influenza. However, depending on where you live, some horse diseases and ailments might be more common than others.

When it comes to your horse’s health, prevention is always better than cure. Nevertheless, if the problem already occurred, recognizing the early signs of disease is key to fast recovery.

Do not hesitate to call the vet if you notice anything off about your horse, as it’s better to be safe than sorry.

Common Horse Diseases


Horse with the Laminitis disease doing a typical Laminitis stance

Laminitis is a painful condition of the horse’s hooves. It happens when the layers of laminae that connect the hoof wall to the internal structures of the hoof are inflamed. Laminitis affects around 1 in 10 horses worldwide and can occur in ponies and donkeys too. (Source: Scott Dunn’s Equine Clinic)

The disease is usually caused by hormonal factors, and many horses with laminitis also suffer from Cushing’s disease or Equine Metabolic Syndrome (EMS).

In the horse world, it is common knowledge that overweight horses are more prone to laminitis as they become insulin resistant which can trigger the disease. Horses that consume too much grain or spring grass at once can also quickly become laminitic.

Laminitis most often shows up as lameness in horses, especially in the front feet. Horses that are more severely affected will display the typical “laminitic stance”, which is when they stand with their forelegs stretched out and the hind legs underneath the body.

Horses with laminitis normally receive painkillers such as bute to help keep them comfortable and reduce inflammation. With this disease, both the farrier and veterinarian’s work is essential to a full recovery. The vet will typically recommend box rest on thick bedding, while the farrier will apply shoes with extra frog support.

Treatment for the disease usually lasts for weeks or even months, and the horse will require careful management after recovery.

Unfortunately, prevention of the disease is difficult in many cases. However, careful weight management, gradual dietary changes, and avoiding a high-sugar diet can reduce the chances of laminitis.

Equine Gastric Ulcer Syndrome

Vet checking a horse for stomach ulcers
hedgehog94 /

Equine Gastric Ulcer Syndrome (EGUS) refers to the formation of painful ulcers in the horse’s stomach. Also known as Gastric Ulcer Disease, it is a common condition that occurs in 50% to 90% of horses. EGUS is most problematic in racehorses and elite sport horses, where the prevalence is almost 100%.

The most common form of EGUS occurs when the unprotected mucosal lining of the stomach is damaged by digestive acids. This can happen during periods of fasting or during exercise on an empty stomach. Hence why it’s important to always have feed material in the horse’s stomach to neutralize the acids.

The signs of gastric ulceration in horses can vary from poor performance to irritable behavior, girthiness, inconsistent appetite, weight loss, and stereotypies. Some horses with stomach ulcers may show no signs at all.

EGUS is most accurately diagnosed by endoscopic examination, which is when the vet passes a camera down the horse’s food pipe to look at the stomach lining. Depending on the severity and location of the ulcers, the vet may prescribe various oral drugs that protect the stomach lining.

Luckily, gastric ulcers can be easily prevented by a good feeding routine. Make sure your horse always has access to grass or hay to avoid fasting, and offer feed or forage 30 minutes before exercise. Also, avoid any abrupt changes to your horse’s diet and introduce new feeds over a period of 4 weeks.

Sweet Itch

Sweet Itch disease on a horse's bum and back

Sweet itch or Summer Seasonal Recurrent Dermatitis (SSRD) is a skin inflammation in horses. It is caused by an allergic reaction to the saliva of female biting midges from the Culicides genus.

Sweet itch is a common horse disease in the United Kingdom, where it affects around 5% of horses. (Source: World Horse Welfare)

Horses suffering from the condition will be itchy along the topline, particularly around the mane and tail. If left untreated, sweet itch can get to the point where the horse rubs itself raw, leaving behind patches of bare skin.

If you suspect your horse is affected by sweet itch, consult your vet about the best ways to relieve the irritation. You might want to consider stabling your horse at dawn and dusk, when midges are most active. Insect repellents and fly rugs can also go a long way toward keeping midges away from your horse’s body.

Azoturia/Tying Up

Horse suffering from Tying Up disease

Azoturia or tying up is the most common disorder affecting the muscles of the horse. It also goes by the names of Recurrent Exertional Rhabdomyolysis (RER) or Monday Mornings Disease.

Tying up essentially refers to the painful cramping of muscles throughout the horse’s body. It most often occurs when unfit horses are exercised too intensely or when hard-working horses are rested for a day and then return to work.

While some horses only experience one or two episodes, others will suffer from repeated cases. According to XLVets Equine, around 7% of Thoroughbreds are affected by recurrent episodes of tying up.

The causes of tying up are not yet fully understood. However, factors that can trigger the diseases include lack of oxygen in the muscles, buildups of lactic acid, and muscle cell death.

Depending on the severity, affected horses will show discomfort, stiff gaits, refuse to move, or even lie down in pain.

If you notice signs of tying up, call your vet immediately. The vet will give the horse pain relief and anti-inflammatory medication, as well as hydrate the horse to restore the electrolyte balance.

To prevent further episodes, make sure your horse is thoroughly warmed up and cooled down before or after work. The vet might also recommend a diet low in carbohydrates and high in fats to help manage the condition.

Also Read: 12 Interesting Facts About the Horse Skeleton

Equine Influenza

Horse sneezing while suffering with Equine Influenza
Mabeline72 /

Just like us, horses can catch the common cold too. According to a survey done in the United States, approximately 17% of equine facilities had at least one horse develop the condition.

Equine Influenza in horses is a viral infection of the upper respiratory tract that can pass from horse to horse. The first sign is usually a yellow or white discharge coming from the nose, and the horse may develop a high temperature and swollen glands in the throat.

Horses most often catch the common cold when they come into contact with other infected horses. This can happen at shows or boarding stables where horses regularly compete. Bad ventilation in stables or trailers can also increase the chances of a horse catching a cold.

As this is a contagious disease, it is important to isolate any horses that show signs of common cold. As always, consult your veterinarian about how to best manage the condition. The vet will also be able to tell when your horse is safe to come out of isolation.

When caring for your sick horse, make sure he is warm and has access to soaked or steamed hay that’s free of dust. To stop the spread of the virus, ensure he also has his own grooming kit, feed bowl, and water bucket.


Vet checking a horse's knee for arthritis
Brastock /

Arthritis or Degenerative Joint Disease (DJD) affects the tissues of the joints and is most common in older horses. According to senior veterinary surgeon Nicola Jarvis, the prevalence of arthritis is over 50% in horses above the age of 15.

Over a horse’s working life, excessive wear and tear of the joints can lead to inflammation and damage to the joint structures. The disease is more prevalent in horses that have been in regular hard work throughout their career.

Arthritis creeps up on horses slowly and may not present any signs at first. However, you’ll gradually start to notice stiffness, heat, and swelling in the affected joint, and eventually lameness.

While there is no definite cure for arthritis in horses, there are various ways you can reduce the pain and discomfort it causes. Keeping your horse in ideal weight will reduce the load on his joints and help him move more easily. You can also ease the stiffness by turning your horse out as much as possible.

Your vet will also prescribe anti-inflammatory medication and may recommend joint supplements.

Cushing’s Disease

Horse suffering with Cushings Disease

Another common old-age condition in horses is Cushing’s Disease or Pituitary Pars Intermedia Dysfunction (PPID). Cushing’s is caused by a hormonal dysfunction of the pituitary gland at the base of the brain.

According to the website Care About Cushing’s, 1 in 5 horses over the age of 15 will develop the condition. Horses with Cushing’s Disease will typically have a long and curly coat all year round. They may also display uneven fat distribution, excessive sweating, lethargy, and poor performance.

Laminitis can also be a sign of Cushing’s Disease. In fact, over 80% of horses with laminitis also suffer from Cushing’s Disease. (Source: Scott Dunn’s Equine Clinic)

While there is currently no way to prevent or cure the disease, horses with Cushing’s can live a long and quality life. The condition can be relatively well managed with drugs and good overall care of the horse.

Also read: What is the Average Lifespan of a Horse?

Common Horse Ailments


Colic is one of the most well-known and feared health problems in horses. This is because it can occur at any time without warning and affects all horse breeds. The outcome of colic is also uncertain and can vary from a quick recovery to death.

Contrary to popular belief, colic is a symptom of abdominal pain in horses and not a disease per se. According to an information sheet of the U.S.D.A, there are generally 3.5 to 26 cases of colic per 100 horses per year. This makes it one of the most common ailments in the species.

Horse that's suffering with colic rolling on it's back

Depending on the cause, there are several different types of colic. The cause will also determine the severity of the colic and the chances of your horse recovering. Colic can be triggered by sudden dietary changes, eating too much straw or spring grass, or twisting/displacement of the intestine.

A colicing horse will be reluctant to move and will often paw the ground, kick out, sweat, look at its belly, lie down and roll. As any colic can potentially be serious, you must call the vet as soon as you notice the signs. In the meantime, walk your horse around on a lead rope to prevent them from rolling.

Most cases of colic are not serious and will resolve on their own. However, some are life-threatening and will require surgery, which is why you need to have the vet out in all cases.

Mud Fever

Lower horse leg that is suffering from Mud Fever
Horse with mud fever. anjajuli /

As the name suggests, mud fever is caused by excessively muddy conditions. You may know it as cracked heels or pastern dermatitis, and is very common in countries with lots of wet weather like the UK.

Mud fever is a painful skin condition in horses where the bacteria Dermatophilus congolensis invades the horse’s body through cracked and damaged skin. This leads to the development of skin infections on the horse’s lower legs that can become painful if the condition deteriorates.

Mud fever most often affects areas with pink skin and will leave nasty scabs around the fetlock area. The infection will initially cause itchiness and scratching, which will in turn bring more bacteria into the skin.

As with many ailments, the prevention of mud fever is much easier than treatment. Once the condition has established, recovery can last several weeks. Your vet may prescribe antiseptic creams to control the infection or antibiotics in more severe cases.

To keep mud fever at bay, limit the time your horse spends standing on muddy fields. Before bringing him into the stable, clean and dry your horse’s legs thoroughly to prevent the skin from cracking. Horses with feathering may benefit from clipping of the lower legs as they are at higher risk of developing mud fever.


Horse suffering from Desmitis

Desmitis refers to the inflammation of a ligament in the horse’s lower legs. It typically affects one of three ligaments, namely the check ligament, the suspensory ligament, and the collateral ligaments in the coffin joint.

Although not widely known, desmitis is a common cause of lameness in horses. Depending on the affected ligament, there might be no clinical signs in the early stages of the condition. The symptoms might be as subtle as slight changes in your horse’s movement or performance.

Because tendons and ligaments are one of the most difficult structures to heal, the treatment for desmitis can last for weeks to months. The vet will likely recommend box rest with regular walking sessions for the first 6-8 weeks. Special shoes might also be needed for horses with collateral desmitis.

The secret of preventing desmitis lies in your horse having strong ligaments. Taking your horse for walks on the road or other hard surfaces is one way to strengthen his tendons and ligaments. This will have the greatest effect when the horse is still young and the structures are malleable.

Rain Scald

Rain Scald or Rain Rot on a horse's back

Rain scald is a fungal skin infection that causes patches of hair loss along the back and hindquarters. Also known as rain rot or mycotic dermatitis, it’s prevalent in horses with weak immunity or poor body condition.

Horses that contract rain scald generally have softened skin due to prolonged wet conditions. This can happen if the horse lacks the natural grease in its coat or is turned out with a leaking rug.

If left untreated, rain scald will cause large hairless patches on the horse’s body, as well as painful sores and lesions. The vet will usually recommend a fungicidal wash to manage the condition.

To minimize the chances of rain scald, make sure there is somewhere your horse can shelter against the rain. Checking your turnout rugs regularly is also important to ensure your horse stays dry on the field.

Also, take our tough horse anatomy quiz!


Horse suffering with ringworm that has round circle patches on it's coat

Despite the name, ringworm is actually a fungal infection in horses. The condition causes circular lesions of various sizes, mainly in the saddle, girth, head, and neck regions. Ringworm is highly contagious in horses and owners must act quickly to prevent an outbreak at the barn.

When a horse contracts ringworm, everything in his environment becomes infectious. The bedding should be discarded immediately, and all equipment washed thoroughly using a fungicidal disinfectant. Brushes and tack must not be shared with other horses, or else the infection will spread.

A horse with ringworm should be immediately isolated from the others until it reaches full recovery. Luckily, the condition is not serious and can be treated with an anti-fungal wash. The vet will also suggest clipping the hair around the lesions as hair can also spread the infection.

Knowing what’s normal for your horse is paramount for spotting early signs of disease and illness. The video below is a useful guide to how to perform a weekly health check on your horse: