.webp)
Rain Scald in Horses: Symptoms, Causes and Effective Measures
Rain scald in horses is uncommon, but it primarily affects horses exposed to continuous rain and those with long, thick coats. Learn how to prevent and treat rain scald here.
Table of Contents
What is rain scald in horses?
Rain scald in horses is a skin infection caused by the bacterium Dermatophilus congolensis. The bacteria penetrate the skin and cause painful crusts and inflammation. Because of the causative bacterium, the medical term for rain scald is dermatophilosis. Colloquially, the condition is also sometimes referred to as rain rot. However, rain scald or rain rot must be clearly distinguished from mange, which is caused by mange mites and can even be fatal for an infected horse. Rain scald is usually not fatal in horses.
The first case of rain scald in Germany became known in 1976, but the disease is still relatively rare in our region. One common trigger is prolonged cold and wet weather, which is why rain scald is more frequently seen in damp climates such as Ireland or Iceland.
Horses with long, dense coats that are exposed to moisture over a long period of time are most commonly affected. The areas most often affected include the croup, back and limbs.
Symptoms: What does rain scald look like?
- Crust-forming pustules
- Affected areas are slightly red and warm
- Circular hair loss around these areas
- Discharge
- Fever
- Sensitivity to touch
- Restlessness and nervousness
The bacteria penetrate the skin barrier and cause inflammation, which is initially only warm and reddened. The neck, croup, back and legs are often affected. Over time, the pustules burst open, discharge appears and crusts eventually form. As a result, the hair around these pustules falls out and, if left untreated, the condition can continue to spread across the body. Within two weeks, the horse may be affected over large areas of the body and lose a significant amount of coat.
The inflammation is painful for the horse. Unlike in cases of sweet itch, the horse usually does not rub itself, but instead becomes sensitive to touch and may react nervously. If the infection is accompanied by fever, the immune system may also be weakened.
Difference between rain scald and sweet itch
Since rain scald in horses mainly occurs in autumn and during cold, wet winters, it may seem like the counterpart to sweet itch. For this reason, some non-professionals also refer to dermatophilosis as winter eczema. However, the two conditions differ significantly in terms of their causes and symptoms, which is why they are fundamentally unrelated.
In order for the bacterium Dermatophilus congolensis to penetrate the skin, it needs an entry point. These are usually tiny, unnoticed cracks, wounds or insect bites. They weaken the skin barrier and allow bacteria to enter. If the horse is also kept in a permanently damp environment, has no opportunity to dry off and has a long, dense coat, ideal conditions are created for the bacteria to multiply.
Stable hygiene also plays an important role, as there are naturally more bacteria in a dirty environment. If the stable climate is also warm, the bacteria have excellent conditions to multiply. The higher the bacterial load, the greater the risk that bacteria will enter small wounds and cause infections.
Why do horses mainly develop rain scald in wet weather?
The name of the condition comes from the fact that this skin disease mainly develops during rain and persistently damp weather. If the horse has no shelter and therefore no chance to dry off, the rain washes away the protective fats from the coat. As a result, the coat loses its water-repellent effect and moisture can penetrate all the way to the skin. The skin becomes fragile and cracked, losing its protective function. Bacteria can then settle in these cracks in the upper layer of the skin and multiply particularly well beneath the airtight crusts that form. Similar triggers can also be seen in mud fever.
The skin is the first line of defence against bacteria. If this barrier is damaged, the immune system can still help prevent the disease from spreading. However, factors such as being underweight, malnutrition or a severe worm infestation can weaken the horse’s defences. This is why horses with a weakened immune system are particularly susceptible to rain scald.
If left untreated, rain scald can spread extensively within just a few days to two weeks.
🎥 Video tip: In the ClipMyHorse.TV Academy, you will find more helpful content on the topic of rain scald in horses – with tips on how to recognise symptoms early, better understand possible causes and support your horse in a targeted way.
Treatment and therapy of rain scald
One of the most important aspects in the treatment of rain scald is good and consistent care of the horse and its skin. In addition to daily care, the owner also needs plenty of patience and perseverance.
Treatment of acute rain scald
In the case of acute rain scald, the first step is to remove the bacteria’s breeding ground by cleaning pustules, wounds and crusts and allowing them to dry. If you have discovered crusty areas, clean them carefully with warm water and an antiseptic soap such as curd soap. Once the crust has softened, you can try to loosen it gently in order to expose the bacteria and destroy their breeding ground.
Once the affected areas have been softened and the crusts have largely been removed, you should dry the wounds thoroughly. Remember that bacteria can multiply particularly well in a damp and airtight environment. This is why the skin needs to be able to dry and breathe. Afterwards, the wounds should be disinfected to further kill the bacteria.
For the care of the pustules and the damaged skin, anti-inflammatory, antibacterial ointments can be helpful in fighting the infection. However, avoid greasy ointments such as milking grease, as they seal the wounds airtight. Underneath, the bacteria can continue to multiply unchecked, which can undo the previous cleaning and treatment.
In horses with long, dense coats that are prone to matting, clipping can be useful in order to improve ventilation of the skin.
The treatment of rain scald is a lengthy process that must be repeated daily. Overall, treatment can take up to six weeks.
Treatment of rain scald by a veterinarian
If rain scald is not treated because it is simply not discovered and diagnosed in time, it can spread across the entire horse within just a few days. Pain, fever and widespread hair loss can be the result. If you discover even small crusty pustules, proceed as described above. Ideally, however, a veterinarian should be called in. Depending on the case, they may also prescribe antibiotics to kill the bacteria. You should especially call a veterinarian if your horse develops a fever or shows signs of pain.
To rule out confusion with ringworm or other skin diseases and to prescribe the correct antibiotic, the veterinarian will take a skin scraping. This is examined under a microscope in the laboratory and the trigger is identified.
Homeopathy for rain scald
Homeopathy is not a primary treatment for rain scald and should only be used as supportive care. The main focus in treating rain scald lies in good and intensive external care, as well as possible internal treatment with antibiotics.
Further measures
Treatment does not stop with the horse itself. In acute cases, you should also clean and disinfect all equipment that has come into contact with the horse. This includes grooming tools, tack, saddle pads, rugs and similar items. For this reason, each horse should have its own grooming and tack equipment to help prevent the transmission of bacteria or fungi.
What can I do to prevent rain scald in my horse?
Rain scald can be prevented by following a few basic principles regarding cleanliness, skin care, stable management and rug management. Keep in mind that it is much easier to prevent rain scald than to treat it.
Horse management: Create dryness & cleanliness
Coat and skin are the horse’s outer protective barriers, keeping many pathogens, bacteria and fungi away from the body. However, if the horse is exposed to constant moisture from rain, dew, mud and similar conditions and cannot dry off in between, these barriers become weakened. The coat loses its protective fatty layer with its water-repellent effect, while the skin softens, becomes fragile and may crack.
No matter how your horse is kept, it should always have access to a dry shelter and dry, clean lying areas. Especially in winter, horses can often be seen standing knee-deep in mud, which can promote mud fever and, in turn, rain scald. The same applies to horses kept on pasture without a solid shelter large enough for all horses in the herd.
A clean stable that is mucked out daily is also essential for keeping horses healthy. Removing manure from the stable significantly reduces the bacterial load and therefore the risk of infection.
The right rug management
If there is no solid shelter available, a waterproof rain rug can help. It protects the skin and coat from rain and is particularly useful for older horses with a weakened immune system. However, caution is still required. Avoid the following mistakes when rugging your horse to support healthy skin:
- Do not put a waterproof rug on a wet horse:
With filled rain rugs, temperatures can rise significantly between the rug and the horse, creating a warm, damp environment if the horse is still wet. The skin softens, becomes fragile and provides the bacterium Dermatophilus congolensis with ideal conditions to multiply. - Check the waterproofing of the rug:
If the rug lets moisture through during prolonged rain, this is counterproductive for the horse’s health. Therefore, regularly check the rug’s waterproofing and reproof it if necessary. Tears should also be repaired to maintain the rug’s function. - Do not rug permanently:
Good skin care also means allowing plenty of light and fresh air to reach the skin and coat. Constant rugging in winter can therefore promote rain scald, especially if the skin is already slightly damaged. Take the rug off your horse regularly and leave it off when your horse is standing in a dry shelter or stable. - Wash the rug at a high temperature and disinfect it:
Before putting the rug on your horse for the first time, you should wash it at a high temperature and disinfect it to kill any bacteria that may have survived during storage.
The same applies to boots and overreach boots in autumn and winter: leave them off whenever possible. Some horses also wear leg protection in the paddock or during turnout. However, dirt and moisture underneath can rub against the skin like sandpaper and cause micro-injuries. If possible, these should therefore be left off or at least cleaned daily.
The right coat care
During daily grooming, you should always keep a close eye out for micro-injuries and wounds. Treat injuries, scratches, tick bites and insect bites with a disinfectant spray or antiseptic ointment to prevent bacteria from entering the skin.
Especially during the muddy season, when horses like to roll, it can be difficult to detect possible injuries. Regularly remove heavy dirt from your horse to prevent matting and clumping of the coat. Horses that tend to develop long coats and matting, under which the skin cannot breathe properly, should be fully or partially clipped.
Needs-based feeding and a strong immune system
Preventing rain scald in horses also includes supporting a strong immune system, which can be promoted through needs-based feeding. A balanced diet tailored to the horse’s requirements can also support the skin barrier. Healthy horses that have access to all necessary minerals and vitamins are generally less at risk of developing rain scald or mud fever.
Vitamin E plays an important role in building and maintaining the skin barrier and can be supplied to the horse, for example, through linseed oil.
The horse can also produce immune-relevant vitamins itself through its gut bacteria. For this, a healthy and balanced gut flora is necessary. This can be supported with sufficient roughage — at least 1.5 kg of hay per 100 kg of body weight — or additionally with brewer’s yeast, linseed and psyllium husks.
Last but not least, the detoxification organs, the liver and kidneys, also contribute to the horse’s immune defence. To support their function, you can feed herbs with a draining effect, such as nettle, birch or willow bark. Dandelion is an important liver herb and can also be fed to help prevent rain scald.
FAQs about rain scald in horses
Is rain scald in horses contagious?
Yes, rain scald can be contagious in horses because it is caused by a bacterium that can be transmitted. However, rain scald is rather rare in Germany, and if you follow a few hygiene and care rules, the risk of transmission between horses is relatively low. Each horse should have its own grooming tools, tack and rugs. Keep an eye on your horse’s skin and treat even small injuries early. This helps reduce the risk of infection.
Transmission to humans can also be possible in principle. Therefore, always wear disposable gloves when treating crusty areas and wash your hands and fingernails thoroughly afterwards.
How long does rain scald last?
How long the skin condition lasts depends on how early it is detected and how far it has already spread. It can take several weeks until the triggers have been fully eliminated and all wounds have healed. Veterinary treatment with antibiotics, alongside daily and thorough care, can help speed up recovery or limit the spread of the skin condition. Depending on the severity, however, it can still take up to six weeks for the horse to fully recover.
Can I ride my horse with rain scald?
Whether you can ride your horse with rain scald depends on the severity of the condition. The inflammation can cause pain and discomfort and is often located on the back, in the saddle area. In some cases, fever may also occur. If the rain scald affects areas of the body that cause discomfort when the horse moves, you should not ride your horse with rain scald. Instead, choose light exercise such as hand-walking.
Which ointment helps with rain scald?
For rain scald, antiseptic and antibacterial ointments can be helpful in killing bacteria. The skin can also be cared for with wound-healing ointments to keep it supple, relieve tension-related pain and help prevent further crust formation.
Please note: Do not use ointments or creams that seal the skin airtight underneath. Ointments such as milking grease create an anaerobic environment in which bacteria can continue to spread unchecked.