Four horses grazing in a pasture

11 Common Horse Skin Conditions and How to Treat Them

Reviewed by Dr. David J.V. Drum DVM MS

Horses often experience various skin conditions that can affect their health and comfort. Recognizing and treating these issues promptly is crucial for maintaining their overall health and happiness. In this guide, we’ll explore common skin conditions in horses, how to identify them, and effective treatment methods to ensure your horse remains in top condition. 

  1. Rain rot (dermatophilosis)
  2. Ringworm (dermatophytosis)
  3. Sweet itch
  4. Grease heel or mud fever
  5. Warts (papillomas)
  6. Hives (urticaria)
  7. Lice infestation
  8. Summer sores (habronemiasis)
  9. Primary seborrhea (dandruff)
  10. Sarcoids
  11. Melanoma

Common horse skin conditions

Without further ado, here are some of the most common skin conditions that affect horses. Maintaining good hygiene, providing proper nutrition, and managing environmental conditions are crucial in preventing many of these conditions. Always consult with your veterinarian for accurate diagnosis and treatment plans tailored to your horse’s specific condition.

1. Rain rot (dermatophilosis)

Rain rot, also known as rain scald or dermatophilosis, is a common skin infection in horses caused by the bacterium Dermatophilus congolensis. Horses typically experience rain rot in wet, humid environments where the extended exposure to moisture compromises your horse’s skin barrier, allowing the bacteria to spread and cause infection. Commonly affected areas include the back, rump, and legs, but it can occur anywhere on your horse’s body.

Symptoms of rain rot

  • Crusty scabs: The most distinctive sign of rain rot is crusty scabs or lesions, often with tufts of matted hair sticking to them.
  • Hair loss: When the scabs are removed or fall off, they often take hair with them, causing bald patches.
  • Pain and sensitivity: Affected areas can be painful to the touch, and your horse might show signs of discomfort or irritation.

Treatment of rain rot

  1. Gently remove any loose scabs using warm water and antiseptic solutions to soften them. Avoid aggressive scrubbing to prevent further irritation and don’t pull on scabs that are still fresh or tight.
  2. Apply antimicrobial shampoos or solutions containing chlorhexidine, povidone-iodine, or similar agents. In severe cases, your veterinarian may prescribe systemic antibiotics to combat the infection from within.
  3. Regular grooming helps keep the coat clean and free from moisture buildup. Be sure to disinfect grooming tools, blankets, and tack to prevent re-infection.
  4. Make sure your horse maintains a balanced diet and good overall health to support its immune system.

2. Ringworm (dermatophytosis)

Ringworm in horses is a fungal infection of the skin, hair, and sometimes hooves caused by dermatophytes. Despite its name, ringworm is not caused by a worm but by a group of fungi that feed on keratin, a protein found in the skin, hair, and hooves.

Ringworm is zoonotic, meaning it can be transmitted from horses to humans. Handling infected horses or contaminated equipment can result in human infection, so it’s important to wear gloves and wash your hands thoroughly after contact.

Symptoms of ringworm

  • Circular lesions: The infection often appears as circular, hairless patches with raised, scaly, or crusty edges.
  • Itching: Affected areas are usually itchy, causing the horse to scratch or rub against surfaces.
  • Multiple lesions: Lesions can be single or multiple and are commonly found on the face, neck, chest, and shoulders.
  • Crusting and scaling: The infected areas may develop crusts and scales, sometimes with a red, inflamed appearance.

Treatment of ringworm

  • Isolate the infected horse to prevent the spread of the fungus to your other horses and animals.
  • Apply antifungal shampoos or creams containing ingredients like miconazole, ketoconazole, or lime sulfur to the affected areas. Follow the product instructions and repeat treatments as necessary. In severe cases, your veterinarian might prescribe oral antifungal medications.
  • Disinfect grooming tools, tack, and any equipment that may have come into contact with the infected horse. Clean and disinfect stalls, fences, and other areas where the horse lives or spends time.
  • Regular grooming and maintaining a clean, dry environment help prevent fungal growth. Avoid sharing grooming tools and tack between horses without proper cleaning.

3. Sweet itch

Sweet itch, also known as summer seasonal recurrent dermatitis (SSRD), is a common and persistent skin condition in horses caused by an allergic reaction to the bites of Culicoides midges, also known as “no-see-ums” or “biting midges.” Sweet itch is most common in the summer months when midges are most active.

Sweet itch is a chronic condition that often requires ongoing management. Working closely with a veterinarian can help develop a tailored plan to minimize the impact on your horse’s quality of life. Early intervention and consistent preventive measures are key to managing sweet itch effectively.

Symptoms of sweet itch

  • Intense itching: The most prominent symptom is severe itching, especially around the mane, tail, belly, and face.
  • Hair loss: Continuous scratching and rubbing lead to hair loss and bald patches in affected areas.
  • Skin thickening: Over time, the skin in affected areas can become thickened and leathery due to chronic inflammation and scratching.
  • Sores and scabs: Persistent scratching can cause open sores, scabs, and secondary infections.
  • Behavioral changes: Horses with sweet itch may exhibit behavioral changes due to discomfort, like restlessness or irritability.

Treatment of sweet itch

  • Preventing midge bites is key. Use insect repellents specifically formulated for horses to deter midges and equip them with fine mesh fly sheets and masks to physically prevent midge bites. Keep horses stabled during dawn and dusk when midges are most active.
  • If midge bites do occur, apply soothing lotions, creams, or sprays containing ingredients like aloe vera, menthol, or corticosteroids to reduce itching and inflammation. Bathe the horse with medicated shampoos to cleanse and soothe the skin.
  • Administer antihistamines to reduce the allergic response (consult with a veterinarian for appropriate medications and dosages). In severe cases, corticosteroids may be prescribed to control inflammation and itching.

4. Grease heel or mud fever

Grease heel, also known as mud fever, scratches, or pastern dermatitis, is a skin condition in horses that affects the lower limbs, particularly the pastern and heel areas. It is characterized by inflammation, scabbing, and sometimes a greasy or oily discharge. It’s often caused by a combination of bacterial, fungal, and sometimes parasitic infections, usually as a result of wet, muddy, or unsanitary conditions.

Symptoms of grease heel

  • Swelling and redness: The skin in the affected area becomes swollen and red.
  • Crusting and scabbing: Scabs and crusts form on the skin, often accompanied by hair loss.
  • Greasy discharge: The condition is named for the greasy or oily discharge that can occur from the lesions.
  • Pain and sensitivity: The affected areas are often painful, and horses may show signs of discomfort or lameness.
  • Cracks and ulcers: In severe cases, the skin may crack, leading to ulcers and more extensive lesions.

Treatment of Grease Heel

  • Gently clean the area with warm water and mild antiseptic solutions, like chlorhexidine or povidone-iodine. Carefully dry the area with a clean towel to prevent further moisture buildup.
  • Gently remove any loose scabs using warm, moist compresses. Don’t pull off scabs that are fresh or still healing.
  • Apply antibacterial and antifungal creams or ointments to the affected area. Barrier creams or ointments containing zinc oxide can help protect the skin from further moisture and contamination. In severe cases, a veterinarian may prescribe systemic antibiotics or antifungal medications to control the infection.
  • Provide clean, dry bedding and avoid exposure to wet, muddy conditions. Consider stabling the horse during wet weather or providing a dry turnout area.

5. Warts (papillomas)

Warts, or papillomas, in horses are benign growths on the skin caused by the equine papillomavirus (EPV). These growths are more common in young horses, typically those under three years old, because their immune systems are not fully developed. While unsightly, these warts are generally harmless and often resolve on their own without treatment.

Symptoms of warts

  • Appearance: Small, grayish, cauliflower-like growths. They can be single or multiple.
  • Location: Commonly found on the muzzle, lips, eyelids, and occasionally the genital area. Less commonly, they can appear on other parts of the body.
  • Size: They vary in size from a few millimeters to several centimeters in diameter.
  • Texture: Typically rough and can feel firm to the touch.

Treatment of warts

  • In most cases, warts in young horses resolve on their own within a few months to a year as the horse’s immune system matures and fights off the virus.
  • If possible, isolate the affected horse to prevent the spread of the virus to your other horses, especially young or immunocompromised ones.
  • In some cases, you can use topical treatments like antiviral creams or ointments to speed up the resolution of warts. 
  • If the warts are causing problems, like interfering with eating or vision, a veterinarian can choose to remove them surgically or through cryotherapy (freezing off the warts).

6. Hives 

Hives are a common allergic skin reaction characterized by the sudden appearance of raised, swollen areas or welts on the skin. These welts can vary in size and shape and are often itchy and uncomfortable for your horse. Hives can appear anywhere on your horse’s body and can be widespread or localized to specific areas. They may last from a few hours to several days depending on the severity of the reaction.

Symptoms of hives

  • Raised welts: Circular or irregularly shaped raised areas on the skin. The welts may be swollen and can vary in size.
  • Itching: Hives are often itchy, causing your horse to scratch or rub against objects.
  • Rapid Onset: Hives can appear suddenly, often within minutes to hours of exposure to an allergen.

Treatment of hives

  • Determine the cause of the allergic reaction if possible and eliminate it from your horse’s environment. This could involve changing feed, avoiding specific plants, or removing certain medications.
  • Rinsing the horse with cool water can help soothe its skin and reduce itching and swelling. Apply soothing lotions or anti-itch creams to the affected areas to provide instant relief.
  • To stop the allergic reaction, administer antihistamines to the affected areas. Always consult a veterinarian for appropriate medications and dosages. In severe cases, vets might prescribe corticosteroids to reduce inflammation and control the allergic response.
  • Make sure your horse’s environment is clean and free from potential allergens in the future. Regularly clean stalls, feed areas, and water sources to minimize exposure to dust, mold, and other irritants.

7. Lice infestation

A lice infestation is a common condition for horses. These pests are species-specific, meaning the lice that infest horses do not infest other animals or humans. There are two main types of lice that affect horses: biting lice (Mallophaga) and sucking lice (Anoplura). Both types can cause discomfort and health issues for your horse.

Symptoms of lice infestation

  • Itching and scratching: Horses with lice infestations often scratch, bite, or rub against objects to relieve the intense itching.
  • Hair loss: Frequent rubbing and biting can lead to patches of hair loss, particularly around the neck, mane, tail, and flanks.
  • Restlessness: Infested horses may appear restless and agitated due to the discomfort.
  • Visible lice and eggs: Small, flat, wingless insects and their eggs (nits) can sometimes be seen on the skin and hair, especially in areas with dense hair.
  • Dull coat: Your horse’s coat might appear dull and unkempt due to the infestation.
  • Weight loss and anemia: Severe infestations, particularly by sucking lice, can lead to weight loss and anemia as the lice feed on your horse’s blood.

Treatment of lice infestation

  • Use insecticidal shampoos, sprays, or powders specifically formulated for lice in horses. Apply the treatment thoroughly according to the product instructions, ensuring it reaches the skin where the lice live. Lice treatments often need to be repeated after 10-14 days to kill newly hatched lice, as most treatments do not kill the eggs.
  • Clean and disinfect all grooming tools, blankets, and tack to prevent re-infestation and exposure to your other horses. Regularly clean and disinfect stables and areas where the horse spends time. Isolate infested horses from others to prevent the spread of lice.
  • Regular grooming helps detect and remove lice before an infestation becomes severe. Perform routine health checks, especially in winter when lice are more prevalent.
  • Quarantine new horses for a period before introducing them to the herd to ensure they are lice-free.

8. Summer sores (habronemiasis)

Summer sores, also known as cutaneous habronemiasis or granular dermatitis, are a common skin condition in horses caused by the larvae of the Habronema and Draschia nematodes, which are stomach worms. These larvae can infest wounds, especially those irritated by flies, and cause localized inflammation and tissue damage. Summer sores typically occur during warmer months when fly populations are high.

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Symptoms of summer sores

  • Raised lesions: Summer sores often appear as raised, granular lesions on the skin, usually around wounds or areas of previous trauma.
  • Swelling and redness: The affected area may become swollen, inflamed, and tender to the touch.
  • Discharge: Summer sores can produce a discharge, sometimes with small, white, rice-like structures (the larvae).
  • Itching and irritation: Horses may exhibit signs of discomfort, including rubbing, biting, or scratching at the affected area.
  • Slow healing: Wounds infested with summer sore larvae may heal slowly or fail to heal altogether due to continuous irritation and inflammation.

Treatment of summer sores

  • To treat summer sores, you should administer anthelmintic medications right away to kill the adult stomach worms and interrupt the life cycle of the parasites.
  • Then, apply topical creams or ointments containing anthelmintic agents (like ivermectin or moxidectin) directly to the affected area to kill the larvae.
  • You can also apply creams containing corticosteroids or antibiotics to reduce inflammation and prevent secondary bacterial infections.
  • Clean the affected area thoroughly with mild antiseptic solutions to remove debris and discharge. Remove any dead tissue or crusts from the wound to promote healing. In some cases, bandaging may be necessary to protect the wound and prevent further irritation.
  • Implement effective fly control measures to reduce fly populations and minimize further infestation. This could include fly sprays, fly masks, fly sheets, and environmental management to eliminate breeding sites.

9. Primary seborrhea (dandruff)

Primary seborrhea in horses is a skin condition caused by an overproduction of sebum (skin oils) and an excessive shedding of skin cells, leading to dandruff-like flakes and sometimes greasy skin. It is a relatively rare condition in horses and is typically a genetic disorder, as opposed to secondary seborrhea, which can result from underlying health issues.

Symptoms of primary seborrhea

  • Flaky skin: The most common symptom is the presence of white or yellowish flakes on the skin and in the coat. 
  • Greasy skin and coat: In some cases, your horse’s skin and coat may appear greasy or oily due to excessive sebum production.
  • Odor: Affected areas sometimes have a distinct, unpleasant odor due to the buildup of oils and skin debris.
  • Thickened skin: Chronic cases can lead to thickened, crusty skin, particularly in areas prone to seborrhea, like the mane, tail, and legs.

Treatment of primary seborrhea

  • Use medicated shampoos specifically designed for seborrhea. Shampoos containing sulfur, salicylic acid, or coal tar can help manage flakiness and reduce oiliness. Ensure that all shampoo is thoroughly rinsed out to prevent further skin irritation.
  • After bathing, use moisturizing conditioners to keep the skin hydrated and prevent excessive dryness. Treat any secondary infections accordingly.
  • Make sure your horse gets a well-balanced diet rich in essential fatty acids, vitamins, and minerals, which can support skin health. Omega-3 and omega-6 fatty acid supplements can potentially improve the condition of your horse’s skin and coat.

10. Sarcoids

Sarcoids are the most common skin tumors found in horses. They are locally aggressive and can appear in various forms, ranging from small, benign growths to large, invasive masses. Sarcoids are typically slow-growing and can occur in any horse breed, age, or sex. While they are usually non-life-threatening, they can be challenging to treat and may recur after treatment.

Symptoms of sarcoids

  • Appearance: Sarcoids can present in different forms, including raised nodules, flat plaques, wart-like growths, or ulcerated masses.
  • Location: They can occur anywhere on your horse’s body but are commonly found in areas with thin skin, like the head, neck, chest, abdomen, and groin.
  • Texture: Sarcoids may feel firm or rubbery to the touch.
  • Variability: Sarcoids can vary greatly in size, shape, and appearance, making diagnosis challenging.

Treatment of sarcoids

  • Small, localized tumors can usually be surgically removed, though sarcoids are known to crop back up over and over. Surgery isn’t always feasible for large or invasive sarcoids.
  • Freezing the sarcoid with liquid nitrogen is another effective treatment for small tumors, although multiple treatments may be necessary.
  • Applying medications like chemotherapy creams or immune-modulating agents directly to the sarcoid can help induce tumor regression.
  • Laser surgery can also be used to remove sarcoids while minimizing damage to surrounding tissues.

11. Melanoma

Melanoma in horses is a type of tumor arising from melanocytes, the cells that produce pigment (melanin) in the skin. These tumors are more common in older horses and are particularly prevalent in gray horses, with studies showing that up to 80% of gray horses over 15 years of age may develop melanomas. While many melanomas in horses are benign, some can become malignant and spread to other parts of the body.

Symptoms of melanoma

  • Lumps and nodules: The primary symptom is the appearance of firm, black or dark brown lumps or nodules on the skin. These are usually found under the tail, around the anus, on the perineum, and near the lips and eyelids.
  • Size and growth: Melanomas can vary in size from small, pea-sized nodules to larger masses and can increase in size over time.
  • Multiple tumors: Horses may develop multiple tumors simultaneously.
  • Ulceration: In some cases, the tumors can ulcerate and become infected.

Treatment of melanoma

  • Surgical removal is often the best treatment for accessible melanomas, especially if they are causing discomfort or functional issues. 
  • Chemotherapy is another common treatment of melanomas, as well as oral cimetidine, which is an antihistamine that has been used with some success to slow the growth of melanomas in horses.
  • Radiation therapy is also used in certain cases where other treatments are not feasible, though it’s less common due to cost and logistical challenges.

Being aware of these common skin conditions will hopefully help you catch any of these issues before they cause too much discomfort to your horse. As always, be sure to partner closely with your veterinarian and seek their advice if you notice any of these symptoms. 

We hope this guide has provided you with valuable insights and practical tips to enhance your horse care routine so you can enjoy the rewarding bond that comes with a happy, healthy horse.

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