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 (de-wormers) 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. Demode 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.
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Treatment

Mange in horses is treated with topical and oral medications according to the specific type of mites present. [4]

Treating different types of mange presents specific challenges. For instance, chorioptic mange in horses can be difficult to treat, with treatment often failing and relapse possible. [10]

In comparison, demodectic mange in horses is not typically treated. Some cases have been reported to resolve spontaneously without treatment. [4]

Always consult a veterinarian before treating your horse’s mange at home. Without a proper diagnosis, treatment attempts may fail and your horse’s condition could worsen.

Lime Sulfur Solution

Lime sulfur is a topical agent used to treat sarcoptic, psoroptic and chorioptic mange in horses. [11] It contains lime (calcium hydroxide) and sulfur, which have parasiticidal properties, making it effective against various types of mites.

Your veterinarian may prescribe a lime sulfur solution, which can be applied through dipping, spraying, or sponging onto your horse’s skin. Treatment should be repeated every 12 days if necessary, following the species-specific dilution instructions on the label.

Anthelmintics (Antiparasitic Drugs)

Although not specifically labeled for the treatment of mange in horses, oral anthelmintic medications have been used to address this condition effectively. [12][13]

  • Ivermectin: Ivermectin administered at a dosage of 200 mcg/kg has been used for the treatment of chorioptic mange in horses. Treatment typically involves administering two doses of ivermectin, spaced 14 days apart.
  • Moxidectin: A single treatment with oral moxidectin, at a dosage of 400 mcg/kg, has also been used for mange in horses.

The off-label use of oral anthelmintic medications for mange treatment in horses should only be undertaken under veterinary guidance to ensure appropriate dosage and safety.

Topical anthelmintic medications may also be administered for psoroptic mange. In one study, 24 horses diagnosed with psoroptic mange were effectively treated with a topical eprinomectin pour-on solution at a dose of 500 mcg/kg body weight once a week for four weeks. [14]

Clipping

Clipping affected horses’ leg feathers is an additional recommendation for treating chorioptic mange. This helps to remove the environment where mites can thrive and reduces their population. It also facilitates the application of topical treatments to the affected areas, improving their effectiveness.

Topical Pesticides

Pesticide sprays such as Permethrin can be used for mange treatment but are not commonly recommended. If used, ensure thorough wetting of affected areas and reapply treatment in 10 to 14 days.

Topical pesticide products (pyrethrin or pyrethroid) may also be used to treat mange caused by trombiculids and straw itch mites. Pesticides specifically designed for equine use can be used to eliminate any larvae that are still actively feeding. Additionally, using repellant products may help prevent infestation. [4]

Inform your veterinarian of all animals who may be exposed to pesticides before treating your horse. Some animals are highly sensitive to pesticides, especially cats.

 

Secondary Treatments for Mange

In severe cases of mange, trauma to the skin due to excessive scratching can lead to secondary skin infections. Severe skin lesions may require additional topical or antibiotic treatment. [2]

To manage the intense itching of mange, symptomatic treatment with a steroid (glucocorticoid) may provide relief. This helps minimize self-trauma and reduces the risk of associated secondary infections. [15]

Prevention

Mange is uncommon in horses, which demonstrates the effectiveness of prevention in eradicating external pests. Strategies to prevent mange in horses include: [2][9]

  • Hygiene: if an infestation is present, it is important to avoid further transmission while treating affected horses. All shared equipment and tack should be cleaned between horses and use gloves when applying topical treatments for mange.
  • De-worming and insect control: staying up to date with current guidelines for de-worming and insect control is the first line of defense against mite infestation.
  • Parasite control: stables or farms with consistent external parasite prevention programs are less likely to have mite infestations.
  • Monitoring and lifestyle controls: when riding outdoors, especially in forested areas, covering your horse in insect repellent and inspecting them for any signs of mites helps prevent infestation.
  • Management practices: adhering to best management practices around animal housing, care (including feeding, handling, and manure disposal), stable sanitation, overcrowding, and separation between susceptible and infested animals is crucial for preventing, controlling, and eradicating mites.

Summary

Mange is a skin and coat condition in horses caused by an infestation of parasitic mites.

  • Mange can cause intense itching, scabs, hair loss, and thickening or scarring of the skin.
  • Sarcoptic, psoroptic, chorioptic, demodectic, and trombiculid mites are common causes of mange in horses.
  • Prompt treatment is crucial to prevent the spread of mange, which can affect various parts of the horse’s body.
  • Diagnosis of mange involves physical examination, skin scrapings, and, in some cases, skin biopsies to confirm mite infestation.
  • Treatment for mange includes topical and oral medications such as lime sulfur solution and anthelmintics. In severe cases, treatment for secondary skin infections may be required.
  • Prevention strategies for mange involve hygiene practices, regular use of insecticides and anthelmintics, parasite prevention programs, and avoiding forested areas.

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References

  1. Mange (Acariasis, Mange Mites) in Horses – Horse Owners. Merck Veterinary Manual. https://www.merckvetmanual.com/horse-owners/skin-disorders-of-horses/mange-acariasis,-mange-mites-in-horses
  2. Mange in Horses: Symptoms, Prevention, Treatment, & More. Equestrian Boots and Bridles. https://equestrianbootsandbridles.com/mange-in-horses/#google_vignette
  3. Mites. Livestock Veterinary Entomology. https://livestockvetento.tamu.edu/insectspests/mites/
  4. Mange in Horses – Integumentary System. Merck Veterinary Manual. https://www.merckvetmanual.com/integumentary-system/mange/mange-in-horses
  5. Ear Mites. HorseDVM Diseases A-Z. https://horsedvm.com/disease/equine-ear-mites
  6. Mites: how to treat them in horses. World Horse Welfare. https://www.worldhorsewelfare.org/advice/mites-how-to-treat-them-in-horses
  7. Kunkle, G. A. and Greiner, E. C. Dermatitis in Horses and Man Caused by the Straw Itch Mite. J Am Vet Med Assoc. 1982.View Summary
  8. Mites.pdf. https://aaep.org/sites/default/files/Guidelines/Mites.pdf
  9. (PDF) Epidemiological studies of equine mange with special reference to different therapeutic protocols for effective treatment of Chorioptic mange. https://www.researchgate.net/publication/346308637_Epidemiological_studies_of_equine_mange_with_special_reference_to_different_therapeutic_protocols_for_effective_treatment_of_Chorioptic_mange
  10. Rüfenacht, S. et al. Combined Moxidectin and Environmental Therapy Do Not Eliminate Chorioptes Bovis Infestation in Heavily Feathered Horses. Vet Dermatol. 2011.View Summary
  11. Paterson, S. and Coumbe, K. An Open Study to Evaluate Topical Treatment of Equine Chorioptic Mange with Shampooing and Lime Sulphur Solution. Vet Dermatol. 2009.View Summary
  12. Brys, M. et al. Alleviating Lesions of Chronic Progressive Lymphedema in Belgian Draft Horses by Successfully Treating Chorioptes Bovis Infestation with Moxidectin 0.5% Pour-On. Vet Parasitol. 2023.View Summary
  13. Article_148484_9dc3a581d9976943791a314b701b116f.Pdf. Ass. Univ. Bull. Environ. Res. Vol. 16 No. 2 October 2013 -29- AUCES EPIDEMIOLOGICAL STUDIES OF EQUINE MANGE WITH SPECIAL REFERENCE TO DIFFERENT THERAPEUTIC PROTOCOLS FOR EFFECTIVE TREATMENT OF CHORIOPTIC MANGE. https://journals.ekb.eg/article_148484_9dc3a581d9976943791a314b701b116f.pdf
  14. Ural, K. et al. Eprinomectin Treatment of Psoroptic Mange in Hunter/Jumper and Dressage Horses: A Prospective, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial. Vet Parasitol. 2008. doi: 10.1016/j.vetpar.2008.06.018.View Summary
  15. Chorioptic,Mites.pdf. https://www.liverpool.ac.uk/media/livacuk/equine/equinepractice/Chorioptic,Mites.pdf