horse grazing in pasture

4 Common Equine Skin Conditions, Causes And Symptoms

It's spring in the South, and that means rain, heat, and humidity. All the things needed to cook up some annoying skin conditions that could throw a wrench into your riding goals this season. This seems like a great time of year to get ahead of whatever skin conditions your horse might be cooking up for you! 

As always before attempting any treatment consult your veterinarian to make sure you're doing the right thing for your horse and where he lives! Treatment can vary significantly by geographic location!

1. Rain Rot ( AKA Rain Scald)

Horse with rain rot

Rain Rot is a fairly common skin condition found among horses, especially those who live out most of the time. It often presents as crusty scabs of matted hair in clusters along the horse’s back and topline. Depending on the severity, it can also run down the shoulders, hindquarters, and legs, and face. The crusty patches fall off, leaving sticky bald spots with or without pus or drainage.

The condition can vary from itchy, too painful, depending on the horse. Rain rot is caused by bacteria known as Dermatophilus congolensis. This bacteria can live on the top of the skin without ever causing any issues or problems. However, a small break in the skin, like a bug bite, can create a path for the bacteria to invade the surface and spread quickly. Age, illness & trouble holding weight as well as having a thick winter coat that traps moisture can make it easier for your horse to get Rain rot. The best thing to do if your horse gets Rain Rot is to alter his living conditions, which may mean spending more time in the barn on wet days. Cleansing the horse's skin with an antifungal shampoo and keeping his skin dry until the condition clears.

2. Scratches (AKA Dew Poisoning)

Horse with scratches

Dew poisoning is one of many names given to the scabby, painful skin condition involving the skin on the back of the pastern & fetlock. Known in different parts of the world as mud fever, greasy heel, or scratches, it's characterized by the formation of painful, crusty, tightly adherent scabs on the back of the horse’s lower leg. Horses with white socks containing pink skin seem to be more susceptible to the condition. The scabs are thought to be caused by overexposure to wet pasture.

Constant exposure to moisture causes the skin to become irritated and inflamed. Eventually, the skin breaks open, allowing bacteria and/or fungal components to penetrate the skin’s surface. Once this occurs, the horse's legs become red, painful & inflamed. The recommended treatment involves moving the horse from the wet environment to keep his legs dry. Additionally, you may need to clip the affected area, to properly cleanse it with antibacterial soap. Once you have cleansed the area, towel dry, and keep the horse out of the wet environment. Do not pick at the scabs, as they are painful, and picking can make them worse. As always, consult your veterinarian before treating your horse to make sure the protocol is correct for your geographic area.

3. Aural Plaques ( AKA Ear Funk)

Horse with aural plaques

Aural plaques are the white crusty sometimes painful, raised lesions on the inside of the horse's ear. Some horses are never bothered by them, others, like my youngster Lego, find them incredibly painful. This mostly only affects him for being bridled or putting a halter on. ( that’s all - nothing important right? )

Like Lego, many horses who find them painful can become ear-shy due to the discomfort. I’m not one for a training workaround unless something is painful, in Lego’s case I had it looked at by a veterinarian and attempted multiple treatments which control it but don’t clear it. So we have made some small accommodations for him. For around the barn we use the buckle on the crown piece and never the cheek snap on his halter, and for bridling I got creative and he has a mule bridle with a snap over crown piece for schooling. Obviously, for competing in the hunters, he has learned to stand still patiently while bridled with open buckles at the cheek and noseband to accommodate his ear.

These crusty lesions are caused by a virus, known as Equus Caballus Papillomavirus. Often during the summer months, owners who deal with Aural Plaques find the discomfort flares up because the flies irritate the plaques. There are many topical treatments available for mild cases; one of my favorites is Dermafas. However, more severe cases may require the use of Imiquimod, which is only available by prescription through your veterinarian and includes a very specific treatment protocol. It should be noted that small tumors in the ears can appear similar to aural plaques, so in some cases, a biopsy may be needed to diagnose the problem. 

4. Ringworm

horse with ringworm

Ringworm is a skin infection caused by one of several dermatophyte fungus species. It is not uncommon for a horse with ringworm, to pass it to his human owner and other animals. The skin starts as small bald raised spots, which progresses into thick dry crusty scabs, which can be itchy or painful. It usually starts as one or two areas but can quickly spread to larger areas and other animals if left untreated. Once the condition is identified, the infected animal should not share grooming tools, riding gear, saddle pads, or boots with other horses in the barn for fear of spreading ringworm.

Horses get ringworm by coming in direct contact with the fungus through another horse, tack, clothing, blankets, grooming tools, or other shared equipment within the barn. The condition can remain on the skin for up to 3 weeks before symptoms appear, meaning that the fungus can spread before you know your horse has it. It is common in horses who are both very young and aged in years simply due to the weakness of the immune system at these stages of life. 


If you think your horse might be experiencing a fungal or bacterial skin infection, it is always best to consult your vet before beginning any treatment regime.

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