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Mange is a skin and coat condition in horses caused by microscopic parasites called mites. [1] Although mange is not common in horses, specific conditions can lead to a mite infestation that can spread rapidly between horses in direct contact. [1]

Mange can affect various parts of the horse’s body including the legs, base of the tail, head, neck, shoulder, girth, and back. [1] The primary symptom of mange is a severe itching sensation (pruritis) that prompts horses to scratch incessantly. [1]

Prompt treatment is critical if you suspect your horse is affected by a mite infestation. Mange-infected horses may need additional treatment for the lingering sores and scabs to aid skin healing.

Anthelmintics (dewormers) are highly effective against mites and are commonly used for treatment. [2] Additional treatments for mange include anti-itching medications, pesticides, and lime sulfur solution. Continue reading to learn more about mange and how to prevent it from infesting your herd.

Mange in Horses

Mange occurs when microscopic mites invade the skin of horses. [1][3] These parasitic mites cause skin irritation and trigger a hypersensitivity reaction, leading to itching, hair loss, and inflammation. [1]

Mange significantly impacts affected horses’ overall well-being. Not only is it uncomfortable, but left untreated, mange can increase susceptibility to other diseases, often due to secondary bacterial infections. [1]

Mange is highly contagious; it can rapidly spread between horses and other animals in direct contact. [1]

Types of Equine Mange

Mange in horses can be caused by several species of mites, each leading to different types of mange. Some of the common types of this condition in horses include sarcoptic, psoroptic, chorioptic, and demodectic mange. [1]

Sarcoptic Mange (Equine Scabies or Body Mange)

Although rare, horses can develop sarcoptic mange or scabies, caused by Sarcoptes scabiei mites. [4] This type of mange is highly contagious and can spread rapidly among horses. [4]

Equine scabies is severe and results in intense itching (pruritus) and hair loss. Hypersensitivity to the saliva and feces of mites often leads to skin lesions. [4]

Lesions start as small bumps known as papules and blisters that subsequently form crusts. Skin becomes thickened (lichenified) and folds develop. [4] Initial signs of sarcoptic mange appear on the head, neck, and shoulders. [4]

Horses diagnosed with sarcoptic mange must be separated from the herd to minimize mite transmission. If a horse has been with a herd before diagnosis, the rest of the horses need to be tested to determine if they’re infested and require treatment. [4]

Left untreated, lesions can spread over the entire body, leading to severe weight loss (emaciation), weakness, and lack of appetite. [4]

Psoroptic Mange (Mane Mange)

Psoroptic mange is caused by two mite species: Psoroptes ovis and P. cuniculi. [4] These mites primarily infest areas of the body covered by thick hair, such as the forelock, mane, base of the tail, hindlegs, and udders. [4]

Mane mange causes severe itching, skin crusting, and hair loss. Headshaking may also occur if mites infest the ear canal. Ear irritation from mites can also lead to inflammation and secondary infection (otitis externa) in severe cases. [4][5]

Psoroptic mange is one of the rarest types of mange and has been eradicated in the United States. [4] However, imported horses can potentially carry mites causing psoroptic mange, underscoring the importance of robust quarantine and biosecurity protocols for introducing new horses to a herd. [4]

Chorioptic Mange (Leg Mange)

Chorioptic mange is caused by infestation with Chorioptes bovis (formerly known as C. equi). It is the most common form of mange that affects horses. [4]

Chorioptes bovis mites primarily affect the lower legs. Draft horses are particularly at risk due to their leg feathering, but this condition can affect all breeds. [4][6]

Itching due to leg mange can cause lesions that mainly affect the lower limbs around the foot and fetlock region in horses. Initially, small bumps appear, followed by hair loss, crusting, and thickening of the skin. [4]

In chronic cases, dermatitis (persistent skin inflammation) may develop in the fetlock area. Clinical signs often lessen during the summer months but resurface when cold and damp weather sets in. [4]

Affected horses often display behaviors such as stomping their feet or rubbing one foot against the opposite leg or an object. [4]

If left untreated, the disease typically persists over time. The prognosis improves significantly with proper treatment. [4]

Demodectic Mange

Demodectic mange in horses results from infestation with Demodex equi or Demodex caballi mite species. Demodex equi resides on the body, while Demodex caballi prefers the eyelids and muzzle. [4]

Demodex equi mites are typically found in hair follicles. These mites reside in oil glands and hair follicles of the eyelids and muzzle. Although rare in horses, they can cause localized hair loss. [4]

While demodectic mange is uncommon in horses, it can manifest in two forms: [4]

  • Patchy hair loss with scaling
  • Nodules on the skin

Lesions from demodectic mange commonly occur on the face, neck, shoulders, and forelimbs. Unlike other types of mange, the demodectic form is not usually associated with itching and scratching, so secondary skin infections and wounds are extremely rare in these cases.

Mange Caused by Trombiculids

Trombiculid mites are primarily found in warm climates. Although typically found on other mammals, these mites can infest horses. They cause intense itching and may lead to secondary infections. [4]

Trombiculid mites are prone to infesting the skin of horses, particularly in late summer and fall, resulting in a condition called trombiculidiasis. [4]

These mites have a unique life cycle. The adults typically inhabit invertebrates and plants, while larvae feed on small rodents. Although horses are not the preferred host, Trombiculid mites will infest equines in the absence of other options. This species can also infect humans. [4]

Trombiculidiasis is characterized by intensely itchy bumps and welts on specific areas of the horse’s body, such as the face, muzzle, limbs, chest, and abdomen. [4]

Mange Caused by Pyemotes tritici (Straw Itch Mites and Forage Mites)

Pyemotes tritici mites infest hay and straw. [7] These mites are transmitted to horses by contact with infested bedding or feed. [1][4]

These mites can cause skin irritation and itching. If infested, horses may develop raised bumps and hives on specific areas. [1][4]

If horses are fed from a hay rack, the lesions appear on the face and neck. If horses are fed from the ground, the affected areas include the muzzle and legs. [1][4]

Causes

The primary mode of transmission for mange in horses is direct contact with infested animals or contaminated environments. Often a horse acquires mites while grazing in an area inhabited by a mite colony. [4]

When the mites sense a suitable host nearby, they swiftly attach themselves to the horse’s skin. Mites can also spread from one horse to another through close contact. [4]

Once mites find their way onto the horse, they begin to bite and burrow into the skin. This leads to intense itching and the formation of raised bumps. [4]

The horse’s scratching exacerbates the situation, causing the bumps to break open, bleed, and eventually scab over. [4]

While the development of anti-parasitic medications has significantly reduced the occurrence of horse-mite interactions, occasional cases still arise. [4]

Mite Survival and Transmission

The mites responsible for mange demonstrate high adaptability to survive and reproduce. When a horse or any animal with a hair coat is present, it offers favorable living conditions for these mites.

Mites do not possess the ability to jump, but they can rapidly migrate from one location to another in search of a host. They move from one host to another, seeking a fresh food source and a new habitat. [4]

Mites are active year-round, depending on climate. In areas of the U.S. where frost is rare, mite populations persist throughout all seasons. Conversely, regions with distinct four seasons typically experience reduced mite activity from late fall to early spring. [2]

Mites have a lifespan of up to 69 days when living on a horse. [8]

Symptoms

Mange in horses is most commonly associated with itching, hair loss, and secondary skin infections. [4]

Other symptoms depend on the severity of mite infestation and may include: [4][9]

  • Scaly skin
  • Skin lumps
  • Hives
  • Thickening of skin in affected areas
  • Blisters
  • Weeping sores
  • Lack of appetite
  • Poor body condition

Early signs of mange may not be readily apparent and can resemble symptoms of various other skin conditions in horses. If you suspect your horse may be affected, consult your veterinarian promptly for a proper diagnosis and treatment plan.

 

Diagnosis

Diagnosing mange in horses requires a thorough examination and often involves a combination of clinical observations and diagnostic tests performed by a veterinarian. Veterinarians may also consider the horse’s medical history, clinical signs, and response to previous treatments when making a diagnosis.

Diagnostic methods for identifying mange include: [4]

  • Physical Examination: The first step in diagnosing mange involves a comprehensive physical examination of the horse. The veterinarian will inspect the skin and coat for characteristic signs of mange, such as hair loss, crusting, scaling, redness, and lesions. They will also assess the distribution and severity of these symptoms.
  • Skin Scrapings: Skin scrapings are a common diagnostic tool used to detect mites under a microscope. During this procedure, the veterinarian will use a scalpel or blunt edge to scrape the surface of the affected skin, collecting samples of skin debris, hair, and mites. These samples are then examined microscopically to identify the presence of mites, their eggs, or other parasites.
  • Biopsies: In some cases, a skin biopsy may be necessary to confirm the diagnosis of mange, especially if other skin conditions or underlying diseases are suspected. During a biopsy, a small sample of skin tissue is surgically removed from the affected area and sent to a laboratory for microscopic examination. Biopsies can provide additional information about the extent of inflammation, tissue damage, and presence of mites within the skin layers.