What is Demodectic Mange?
Demodectic mange is not common, but it has been found in all areas of the world in both males and females, all ages, and every breed. The demodex mites will cause your horse to become aggravated, extremely itchy, and stressed out so it is important to make an appointment with your veterinarian as soon as possible. Most horses have demodex spp mites on their bodies, but they usually do not cause any symptoms in healthy horses. Therefore, if your horse has demodectic mange, you should be sure to have the veterinarian do a complete physical examination when you visit.
Demodectic mange (demodicosis or red mange) is the result of bites caused by the demodex spp mite. There are five types of demodex mites but the most common are demodex equi, which can affect the whole body, and demodex caballi, which prefers to live on the eyelids. The most common places to find the demodex equi are the shoulders, face, and neck. However, it is possible to find the mites anywhere on the body, especially if it is a severe infestation or has gone untreated for a long time. The relentless scratching and biting at the affected areas can cause secondary bacterial infection as well, which can create even more discomfort for your horse.
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Symptoms of Demodectic Mange in Horses
The symptoms your horse has depends on the severity of the infestation.
- Scratching more than usual
- Hair loss
- Foot stomping
- Rubbing against stationary structures
- Crusty scabs
- Flakes in the hair
- Skin infections
- Leg flexing
There are five different kinds of demodectic mange that have been found on horses, which are:
- Demodex aries is usually confined to the nostrils, prepuce, and vulva
- Demodex caballi is a harmless mite of the Meibomian glands
- Demodex cati is found in the ear canals and head
- Demodex equi can be found anywhere, but mostly on the shoulders, neck, and head
- Demodex ovis is not usually noticeable and infests the sebaceous glands and hair follicles of the entire body, but mostly on the neck, shoulders, and head
Causes of Demodectic Mange in Horses
The cause of demodectic mange is the bite from demodex equi or demodex caballi mites, but the underlying cause is the important thing to determine. Some of the causes include:
- Lengthy usage of glucocorticoids
- Cushing’s disease
- Nutritional deficiency
- Chronic disease
Diagnosis of Demodectic Mange in Horses
Your horse will need to see a veterinarian, preferably an equine veterinarian, to check for demodectic mange. Similar to other veterinary visits, the veterinarian will need your horse’s history and a complete physical examination. Even if the veterinarian is able to verify that your horse has demodectic mange right away, it is essential to rule out other conditions such as sterile eosinophilic folliculitis, dermatophilosis, dermatophytosis, and staphylococcal folliculitis. Tell the veterinarian about any previous injuries, illnesses, abnormal behavior and appetite, symptoms you have noticed, and any medications your horse is on.
The physical examination will include body temperature, height, weight, reflexes, blood pressure, breath sounds, body condition score, heart rate, and respirations. Diagnostic tests should include a biopsy of skin scrapings, urinalysis, fecal examination, complete blood count (CBC), chemical analysis, packed cell volume (PCV), adrenocorticotropic hormone (ACTH), cortisol, and glucose for Cushing’s disease. In addition, the veterinarian may do some x-rays and a CT scan to check for other underlying disorders.
Treatment of Demodectic Mange in Horses
To treat your horse for demodectic mange, the veterinarian will need to be sure what caused it because healthy horses do not usually have any reaction to the demodex mites that normally live on the body.
A pergolide drug called Prascend will be used to treat Cushing’s disease. It is the only FDA approved drug for this illness. Supportive care will also be given to help with any complications.
If your horse has a chronic disease, the veterinarian has to do what is possible to build natural immunity so this will not happen again. This may include vitamins, a special diet, or medication.
To treat a nutritional deficiency, the veterinarian will most likely prescribe vitamin supplements and a special diet.
If your horse has been on glucocorticoids for a long time, the veterinarian will discontinue the medication until the mange clears up. There may be a different medication to use for your horse’s condition or the veterinarian may decide the drug is not needed anymore. This depends on why your horse was taking it in the first place.
Cleaning and Disinfecting
To clean and disinfect, the veterinarian will clip any long hairs in the affected areas and wash with a special antibacterial soap. A brush will be used to scrape away any dead skin and crusts so the skin will absorb the medication.
A medicated shampoo such as lime sulfur dip, organophosphates, or rotenone liquid will be used next.
Some of the most commonly used drugs used are ivermectin cream, benzyl benzoate lotion, sulfiram, fipronil, and diazinon. Use of trichlorfon 2% applied to the affected areas every other day has been very successful. Daily doramectin or ivermectin may also be effective in many cases. Also, antibiotics will be given to prevent infection and anti-inflammatory drugs to help with inflammation and itchiness.
Recovery of Demodectic Mange in Horses
Your horse has an excellent chance of recovering from demodectic mange if the underlying illness is treated. With Cushing’s disease, you will need to discuss with the veterinarian regularly scheduled wellness visits. This is a lifelong illness that has to be maintained carefully. No matter the cause, you should call the veterinarian with any questions or concerns.