Demodectic Mange Information from Your Veterinarian in McKinney

By Dr. Ed Mapes

One type of mange we see more often than others is caused by a mite called Demodex folliculorum.  This is a microscopic insect that lives in the hair follicles and causes hair loss in dogs.

This usually occurs in young dogs, often puppies.  It is thought that their immune systems fail to suppress the mites, allowing them to exist and produce symptoms.  Short-haired breeds are most commonly affected: Dachshunds, Pit Bulls, and Boxers are the most frequent patients with this mange.

The dogs are often unaware of the lesions, since there is usually no itch associated unless a bacterial infection arises secondarily.   We see patchy hairless areas of the front legs, face and head, and shoulder areas; but cases can become generalized and involve most of the body.

The more severe cases involve skin inflammation and infection, extensive hair loss, thickening of the skin, and the dogs can run fevers and become lethargic.  These dogs will begin to scratch at the inflamed skin.

We diagnose Demodex by using a test known as a skin scraping.  Hair is clipped from around the suspected lesion, and then we squeeze the skin to force mites closer to the surface.  Using a surgical scalpel, we then carefully scrape the skin to remove the top layers of dermis.

The scraped material is placed on a microscope slide, and we scan to identify the insects.  They resemble submarines with legs and mouth parts at one end – the legs and head are usually still moving.  It is interesting to bring pet owners into the lab area, where we transmit the microscopic image to the computer for viewing; people are usually surprised at the appearance of the mites.

Here is a video of an actual moving Demodectic Mange:

Treatment of Demodectic mange depends on whether the condition consists of only a few lesions or a more serious generalized case.  Ivermectin is a drug used to kill the mites, but we are very careful to control the dosage to prevent side effects.  The schedule calls for very low doses initially, gradually increasing for a more potent effect.

Side effects in dogs include:

  • vomiting
  • dilated pupils
  • muscle tremors
  • blindness
  • incoordination
  • lethargy
  • lack of appetite
  • dehydration

I have never seen adverse reactions when pet owners stick to the prescribed schedule of administration.  We recheck patients after two weeks to monitor progress and prescribe dosing for the next two weeks.  This continues until we’ve had two skin scrapings with negative results.

Medications used in conjunction with Ivermectin include antibiotics, medicated shampoos, and omega-3 fatty acids.  There is often a noticeable improvement within the first two weeks of therapy, but complicated cases can involve weeks of treatment.  Patients usually re-grow hair in affected regions after the mites are eradicated, and there should be no permanent scarring of the skin.

Pet owners are advised to have any pets displaying small areas of hair loss examined by a veterinarian in McKinney TX.  Demodex, and other forms of mange as well, are easier to treat when we make early diagnoses.

Veterinarian in McKinney
Stonebridge Animal Hospital
5913 Virginia Parkway, Ste 100
McKinney, TX 75071
(469) 507-2433


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