Eight Common Equine Skin Conditions: Treatments & Causes




Rain Rot – sometimes called rain scald. 

Appearance: Usually appears on the shoulders, back and rump area.  Crusty bumps with tufts of hair standing upright.  Small round bald spots that may be pus filled where hair tufts have fallen out.

Cause: Bacterial infection, multiplies rapidly in a moist environment.  A small break in the skin allows the bacteria to enter and become infected. Skin damage caused by biting insects or chaffing from ill-fitting tack can allow the bacteria into the skin.  Thick winter coats can easily trap moisture and bacteria and allow the infection to thrive.

Treatment: If the weather is damp, it’s best to place the infected horse in a dry, covered area until cleared of the rain rot.  Treat with an anti-bacterial shampoo or anti-bacterial spray, daily for at least a week.  Depending on the severity of the infection, it may take longer.  Spot treatment may be effective if only a small area is infected.  Use a shedding blade  to rake off scabs and hair tufts to accelerate the healing process, exposure to air will help kill the bacteria. 

Prevention: Provide adequate shelter for your horse to escape to during wet weather.  Regular grooming will prevent dirt and mud from holding moisture against the skin.  This will also help you spot the early signs of rain rot so it can be treated before it spreads.  Always disinfect blankets that come in contact with an infected horse.


Appearance: Similar to rain rot, small circular hairless patches of crusty, scabby skin.  Lesions often appear on the face, neck, shoulders, chest, and under the saddle or girth area. 

Cause: Fungal infection, highly contagious, it is not an actual worm. The fungus consumes keratin, the protein that forms hair and skin cells.  Spread from animal to animal.

Treatment: The infected horse should be separated from other animals.  Clip the hair around the lesions to remove the organism source of food.  Wash the horse with an anti-fungal shampoo.  Clean the area with an antiseptic and thoroughly dry.  Apply an anti-fungal ointment or spray.  Air and sunlight will help kill the fungus.  Depending on the severity of the infection, several applications may be needed.

Prevention:  Quarantine new horses for at least ten days to ensure they aren’t carrying any infections, to include ringworm.  Always wear gloves when treating infected horses.  Disinfect tack, stalls and other areas when you have an outbreak with a premises disinfectant.   


Appearance: Raised gray or pink cauliflower like growths, usually small.  Warts may appear in clusters on the muzzle, sometimes found on the lower lips, ears or genitals.  They do not appear to cause pain or discomfort unless found in the corners of the mouth where the bit may rub and irritate.

Causes: Caused by the Equine Papilloma virus, an organism that lives on the skin and tack for weeks.  Most often affects young horses, under the age of three. 

Treatment: Generally the warts will disappear without treatment as the young horses immune system develops.  This may take up to four months.  If they do not go away in a reasonable time, your vet should examine them to ensure the warts aren’t a sign of a more serious, underlying condition.  It is best to isolate infected horses and disinfect tack and stable areas.

Dandruff - Primary Seborrhea

Appearance:  Can be dry or oily.  A dry dandruff will produce dry, flaky skin, generally at the base of the mane and tail.  An oily dandruff will appear as large waxy crusts, often found on the elbows, knees and lower legs.  Dandruff can sometimes have a foul smell.  This is caused by the decaying skin. 

Causes: Most commonly hereditary, found mostly in Arabians and Thoroughbreds. 

Note: Secondary Seborrhea, the sudden appearance of dandruff in a horse that has not previously experienced the condition, can be a sign there is a more serious illness.  The sudden onset of dandruff could be a sign of liver or intestinal disease and should be investigated by your vet.

Treatment: There is no cure for primary seborrhea, dandruff, but it can be managed very well with an anti-dandruff shampoo.  Secondary Seborrhea will likely clear up when the underlying condition is treated.

Prevention:  Regular grooming and feeding vegetable oils or supplements with Omega 3 fatty acids and biotin will help control the dandruff.


Appearance: A sort of skin tumor, sometimes resembling proud flesh, it is often benign and non-life threatening but can be locally invasive.  There are many types of sarcoids:

1. Nodular sarcoids are firm, raised circular nodules.  Generally found on the sheath/groin area and eyelids.

2. Fibroplastic sarcoids are fleshy and ulcer like.  Generally found on the groin, lower legs and eye lid.

3. Verrucous sarcoids look a lot like warts, but unlike warts will not go away or decrease in size.  Generally found around the face, jaw, body and groin area.  Verrucous are the most common.

4. Occult sarcoids are circular, flat and thickened areas.  Generally found on the mouth, eyes, neck and inner leg areas.

5. Malevolent sarcoids are clusters of nodules under the skin surface, appear to look like cords under the skin. Can appear anywhere on the body, head or legs.  They are invasive and can enter the lymphatic system.

6. Mixed, may be a combination of all the above.  Generally mixed sarcoids are caused by a trauma or on a horse that has been affected with sarcoids for a long period of time.

Causes: It is suspected that Bovine Papilloma Virus (BPV) is a factor in causing sarcoids and believed it is spread by biting flies.  Because it is a virus, it can be assumed that sharing infected tack could also spread the sarcoid to other animals.  Sarcoids may appear suddenly or at the site of a trauma.  Most commonly appear in horses under four years of age.

Treatment:  A positive diagnosis can only be made through a skin biopsy conducted by your vet.  However, when a sarcoid is irritated it will often worsen and spread and recurrence of the tumors is common.  A sarcoid cream may help prevent reoccurrence of the tumor.  Unless it is causing the horse pain, many vets will opt not to treat the sarcoid at all. 

Prevention:  No vaccine is currently available to prevent sarcoids.  Fly prevention in wounds is crucial.  Wounds should be treated with fly control salve.


Appearance:  Small or large bumps that may cover the entire body or large portions.

Causes: Hives are most commonly caused by an air born allergy.  They may also be a reaction to a medication or vaccination.

Treatment: Hives are usually not painful, just itchy and will clear up without medication.  An anti-itch shampoo  or spray will alleviate any discomfort your horse may be experiencing.

Insect Hypersensitivity

            Appearance:  Rash like, small bumps located in a concentrated area.

            Causes:  Thought to be caused by an allergic reaction to the saliva of insects. 

            Treatment: A medicated shampoo or spray will help alleviate itching.

Prevention: A good insect control is the best way to prevent insect bites.  Fly sheets and leg protection are also helpful.  Installing an automatic fly spray system in barns will dramatically decrease insect populations. 

Sweet Itch – sometimes referred to as summer eczema

Appearance: Small itchy bumps, usually concentrated around the mane and tail head.  Scabbing and hair loss usually occur from the excessive rubbing and itching.

Causes: A reaction to the salivary antigens from the bite of Culicoides gnat, aka midges or “no-see-ums”. 

Treatment: An anti-itch spray will help alleviate the intense itching.  An ointment may be necessary in areas that have been rubbed raw.  A good hair and skin conditioner will promote regrowth of hair.

Prevention: A good insect control is the best way to prevent insect bites.  Fly sheets, fly masks and leg protection are also great products to protect your horse from most biting insects.

                   “The horse knows.  He knows if you know.  He knows if you don’t.” ~ Buck Brannaman

Christy Wells

Christy has been riding, training and handling horses for 25 years including several years in the rodeo circuit.

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