Chorioptic Mange in Horses
- Chorioptic mange is the most common form of mange in horses and is caused by the mite *Chorioptes bovis*.
- It usually affects the lower legs and fetlocks, especially in draft horses and horses with heavy feathering.
- Common signs include itching, stamping, rubbing the legs, crusting, hair loss, and thickened skin.
- It is usually not a same-day emergency, but your horse should see your vet promptly because untreated cases can become chronic and lead to secondary skin infection.
- Diagnosis is typically made with a physical exam plus skin scrapings, and some horses need repeat scrapings or biopsy if mites are hard to find.
What Is Chorioptic Mange in Horses?
Chorioptic mange, often called leg mange, is a skin disease caused by the mite Chorioptes bovis. In horses, it most often affects the distal limbs, especially around the fetlock and foot. Merck Veterinary Manual describes it as the most common form of mange in horses, with draft horses commonly affected, though any breed can develop it.
These mites live on the skin surface rather than deeply burrowing. Even so, they can trigger significant irritation and itchiness. Horses may stamp their feet, rub one leg against the other, or scratch on fences and stall walls. Over time, the skin can become crusty, thickened, and inflamed.
Many cases flare during colder months and improve in summer, then return when winter hair and feathering come back. That seasonal pattern can make the problem seem mild at first, but chronic cases can be frustrating and uncomfortable without treatment.
The good news is that prognosis is usually favorable with appropriate care. Your vet can help confirm that mites are the cause, since chorioptic mange can look similar to pastern dermatitis, allergies, lice, or other skin problems.
Symptoms of Chorioptic Mange in Horses
- Itching of the lower legs and fetlocks
- Stamping the feet or repeatedly lifting and rubbing the legs
- Small bumps or papules around the fetlock
- Hair loss in feathered areas or around the pasterns
- Crusting, scaling, or dandruff-like debris on the lower limbs
- Thickened skin from chronic irritation
- Moist dermatitis or greasy, inflamed skin at the fetlock
- Raw skin, sores, or signs of secondary bacterial infection
Many horses with chorioptic mange are bright and eating normally, but the skin changes can steadily worsen if mites are not addressed. See your vet sooner if your horse is intensely itchy, has open sores, swelling, heat, lameness, or foul-smelling discharge from the lower legs. Those signs can mean secondary infection or another condition that needs a different treatment plan.
What Causes Chorioptic Mange in Horses?
Chorioptic mange is caused by infestation with the mite Chorioptes bovis. These mites tend to live on the skin surface and are especially associated with the feathered lower legs of draft horses, but they can affect any horse. Close contact with an affected horse, shared grooming tools, and contaminated housing or bedding can all help mites spread.
Heavy feathering creates a warm, protected environment where mites and skin debris can build up. That is one reason draft breeds are overrepresented. AAEP guidance also notes that clipping hair and removing crusts and debris can improve control, because treatment reaches the skin more effectively.
Cold weather often makes the problem more noticeable. Merck notes that signs commonly subside in summer and recur with the return of cold weather. Horses with chronic skin irritation, muddy legs, or concurrent skin disease may also have a harder time clearing the infestation.
It is important not to assume every itchy pastern is mange. Pastern dermatitis, bacterial or fungal skin disease, lice, contact irritation, and allergic conditions can look similar. Your vet can sort through those possibilities and build a plan that fits your horse and barn setup.
How Is Chorioptic Mange in Horses Diagnosed?
Diagnosis usually starts with a hands-on exam and a close look at where the lesions are located. Chorioptic mange often targets the lower limbs, especially the fetlocks and feathered areas. Your vet will also ask about seasonality, whether other horses are itchy, and whether the horse has had recurring pastern skin problems.
The most common test is a skin scraping. Material from the affected area is placed on a slide and examined under a microscope to look for mites. In some horses, especially if lesions are chronic or treatment has already started, mites can be harder to find. That means a negative scraping does not always fully rule out a mite problem.
If the diagnosis is still unclear, your vet may recommend repeat scrapings, tape prep, skin cytology, fungal testing, or a biopsy. These tests help separate chorioptic mange from pastern dermatitis, bacterial infection, dermatophytosis, lice, or allergic skin disease.
Because treatment choices differ, getting the diagnosis right matters. A horse that looks like it has "greasy heel" may actually have mites, or it may have both mites and secondary infection at the same time.
Treatment Options for Chorioptic Mange in Horses
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Office or farm-call exam
- Skin scraping to look for mites
- Clipping feathered hair on affected legs if your vet recommends it
- Topical therapy such as lime sulfur or a labeled permethrin-based product, repeated as directed
- Basic environmental cleanup: wash brushes, disinfect shared tools, replace or clean bedding
Recommended Standard Treatment
- Exam plus skin scraping, with repeat scraping if needed
- Clipping and cleansing of affected feathered areas
- Topical treatment plan such as lime sulfur at label intervals and/or labeled acaricidal spray
- Systemic antiparasitic treatment selected by your vet, such as oral ivermectin or moxidectin when appropriate
- Treatment plan for in-contact horses on the property when indicated
- Recheck exam to confirm response and address lingering skin inflammation
Advanced / Critical Care
- Full dermatology workup if diagnosis is uncertain
- Repeat skin scrapings, cytology, fungal testing, and possible biopsy
- Culture or targeted treatment for secondary bacterial infection if present
- Pain, itch, and inflammation management tailored by your vet
- Detailed herd and environmental control plan for persistent or barn-wide outbreaks
- Referral or consultation for chronic, severe, or treatment-resistant cases
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Chorioptic Mange in Horses
Bring these questions to your vet appointment to get the most out of your visit.
- Does this look like chorioptic mange, pastern dermatitis, or could both be happening together?
- What tests do you recommend to confirm mites, and do we need repeat skin scrapings if the first one is negative?
- Should my horse's feathering be clipped before treatment?
- Which topical treatment do you recommend, and how often should it be repeated?
- Do the other horses, donkeys, or mules on the property need treatment too?
- What should I clean or replace in the barn to reduce reinfestation?
- Are there signs of secondary bacterial or fungal infection that need separate treatment?
- When should we schedule a recheck, and what signs would mean the plan needs to change?
How to Prevent Chorioptic Mange in Horses
Prevention focuses on reducing mite exposure and making the lower legs a less friendly place for mites to persist. Good barn hygiene matters. Clean and disinfect shared brushes, wraps, and grooming tools, and avoid sharing equipment between horses with active skin disease. Fresh bedding and regular stall cleaning can also help reduce re-exposure.
Quarantine new arrivals before introducing them to the herd, especially if they have feathered legs, dandruff, crusting, or itching. If one horse is diagnosed, ask your vet whether in-contact horses should be checked or treated too. On some farms, controlling the environment and the whole group is the difference between a one-time problem and a recurring winter cycle.
For horses with heavy feathering, routine leg care is important. Keeping feathers clean and dry, managing mud, and removing excess crusts under veterinary guidance can help. AAEP notes that clipping hair and removing skin debris improves treatment effectiveness, and that same principle can support prevention in horses with repeat flare-ups.
There is no vaccine for chorioptic mange. Prevention is really about early recognition, prompt veterinary care, and barn-level management. If your horse starts stamping, rubbing, or developing crusty fetlocks each winter, bring it up with your vet before the skin becomes chronically inflamed.