Strange lumps, itching, bald spots, redness, skin flaking, and scruffy patches are common signs of skin problems in horses.

While most equine skin irritations don’t present serious health risks, persistent skin problems can lead to infections and could indicate allergies, systemic inflammation or other health concerns. [1]

Identifying the underlying cause of skin issues is key to alleviating symptoms and preventing recurrence. Bug bites, mud, poorly fitted tack, bacteria and fungi are all common causes of dermatological issues in horses.

This article will review the identification, causes, treatments, and prevention of common skin irritations in horses. We will also discuss how to support equine skin health and manage horses with skin problems.

Common Equine Skin Problems

Equine skin irritations can arise from several different causes, including allergies, parasites, trauma, burns, chemical irritants, or diseases caused by bacterial infections, viral infections, fungal infections, parasites, or allergies. [1]

Skin problems are usually accompanied by dermatitis – a general term that describes skin inflammation. Other signs of irritation include:

  • Hair loss and bald spots
  • Bumps or hives
  • Thickened skin
  • Scaling or dandruff
  • Skin redness
  • Itching and discomfort
  • Skin lesions with or without fluid discharge

Early identification is vital for the effective management of many equine skin diseases. Horses with skin inflammation are at risk of secondary bacterial infections if the skin’s immune barrier function is compromised.

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Causes of Skin Irritations

Here are some common skin conditions that horse owners should learn to recognize.

Rain Scald

Rain scald, or rain rot, is a bacterial skin infection that affects the horse’s rump and back. Dry and scaly skin is the first symptom. In advanced cases, horses develop crusty lesions and scabs with upright tufts of hair. [2]

Under the scabs, raw skin may discharge sticky yellow exudate. The secretion causes hair to matte together. Bald spots and areas of hair loss occur when scabs detach from the skin. [3]

This type of dermatitis can also affect areas of the barrel, shoulders, hindquarters, face, and lower legs.

Causes

Rain scald is caused by the bacteria Dermatophilus congolensis. This opportunistic organism is naturally present on the skin and multiplies rapidly in a moist environment. [2]

When excessive moisture weakens the skin’s protective barrier, the bacteria invade the epidermis and result in infectious lesions. [2]

Treatment

The horse’s skin must remain dry while being treated for rain scald. Allowing the coat to dry out will reduce recovery time and aid the healing process.

Washing the skin with chlorhexidine scrub and soaking it in a saline solution helps remove crusty skin. Some local lesions respond to treatment with topical silver sulphadiazine. In rare cases, your veterinarian may prescribe systemic antibiotics. [2]

Rain scald lesions usually heal without scarring. Mild cases usually subside within two to three weeks.

Prevention

Horses that live outside in wet conditions have a higher risk of rain scald. Always ensure horses have access to adequate shelter and consider stabling your horse to let their coat dry. Waterproof blankets can also protect horses from excess moisture during turnout. [2]

Rain scald is contagious. Regularly disinfect equipment that contacts an affected horse and avoid sharing brushes with other animals to prevent infection.

Pastern Dermatitis

Also known as scratches, mud fever, or greasy heel, pastern dermatitis refers to multiple conditions that cause skin irritation on the horse’s pastern.

Mild forms of pastern dermatitis cause redness, itchiness, and hair loss. More severe cases involve skin lesions on the pastern and heel that produce oily secretions. [4]

These clinical signs can progress to tissue granulation or proud flesh. Horses with advanced pastern dermatitis can experience significant pain and become lame. [4]

Causes

Pastern dermatitis has multiple causes, but microbial infection is the most common. Several strains of bacteria are associated with the conditions, including Dermatophilus congolensis. [5]

Other infectious causes of pastern dermatitis include soil-borne fungi and parasites. Parasitic mites associated with pastern dermatitis damage the skin and allow pathogenic microorganisms to enter. [4]

Underlying health conditions can also predispose horses to pastern dermatitis by weakening the horse’s skin barrier and immune system. [4]

Treatment

Veterinarians must first identify the root cause of pastern dermatitis to recommend an effective treatment. They may collect skin samples to test for bacteria, fungi, or parasites. Blood tests can help rule out underlying health conditions. [4]

Effective treatments for pastern dermatitis aim to stop the source of infection or skin damage, allowing the skin to heal. Treatment typically involves applying topical medications to affected patterns.

Depending on the diagnosis, your veterinarian may recommend an antibacterial, antiparasitic, or antifungal cream. [4]

Prevention

Risk factors for pastern dermatitis include wet conditions, sandy footing, dirty bedding, incorrect bandaging, insect bites, and thick pastern hair. [4]

Horse owners can help prevent pastern dermatitis by keeping the lower legs as clean and dry as possible. Limit exposure to muddy conditions in turnout and dry legs thoroughly after bathing to avoid excessive moisture weakening the pastern skin.

Abrasive substances can also irritate the pastern skin. Wash work boots and thoroughly clean your horse’s legs after riding in a sandy arena to avoid skin irritation.

Ringworm

Ringworm, or dermatophytosis, is a highly contagious and relatively common skin disease in horses. This disease affects the hair and epidermis.

The first sign of ringworm is a change in the angle of the hair shaft. The altered angle creates small, often circular, patches of hair that stand out from the rest of the coat. [6]

Eventually, hair loss reveals round patches of scabby, crusty skin. These lesions are common on the chest, neck, shoulders, and face. But ringworm can occur anywhere on the body. [6]

Causes

Ringworm is a fungal infection generally caused by organisms in the Trichophyton and Microsporum families. These fungi are dermatophytes that consume keratin, a protein in hair and skin cells. [6]

Fungal spores can survive for extended periods in barn environments, and transmission occurs when horses come in co