You & Your Pet by Dr. Wise

Rhode Island Veterinary Medical Association 11 South Angell Street #347 · Providence, RI 02906 (401) 751-0944(401) 780-0940 · Fax · rivma@rivma.org

My four-year-old blue heeler/collie mix has been scratching so severely that he is losing his hair.  I have also begun scratching.  You might think I am paranoid, but could we have the same thing?  I have heard that people and dogs can get mange.  Is this true?

What you have heard is correct.  Both humans and dogs, along with most other mammals, can get a variety of mange, known as Sarcoptes scabei, or scabies.  There are many other types of mange that are not contagious to humans.

Scratching occurs because of the skin irritation (and annoyance) that the mites cause.  Clinical signs that are found in dogs include hair loss and extremely red and itchy skin.  Diagnosis is determined by either skin scraping or a skin biopsy.  To obtain a sample, an inflamed area of skin is chosen and squeezed at different angles.  A scraping is then done until blood is seen.   Scrapings must be made deep enough to draw a little blood to find the majority of the mites.  Because this particular mite burrows very deep into the skin, sometimes a surgical biopsy is needed to identify the mites.  A simple scraping can be read using a microscope. 

There are a number of treatments that can be done to eliminate the mites.  Initially, a bath is given to remove crusts from the skin.   There are several types of dips that are used as treatments.  Injections can also work effectively, as well as an oral medication.  Often, what works in one part of the country is not what works in another, because of resistant mite strains that exist geographically. Sometimes all pets in the household, as well as the house itself, need to be treated to fully eliminate the mites.  Please see your veterinarian for a diagnosis and treatment plan. 

Scabies produces an intense itchiness in people, but because the mite cannot live out its normal life cycle on humans, the irritation is usually very short lived.  Most physicians recommend treatment, though, so be sure to contact your doctor.

We recently adopted a four-month-old puppy.  He seems to be very healthy except for his skin.   He’s chewed and scratched his lower legs and chin until the hair is thin and wearing away.  We found no fleas. Our neighbor thinks he has mange.  What is mange and what do we do?

One of the more unpleasant skin diseases affecting small animals, and dogs in particular, is mange. Even the name has an unpleasant sound, and certainly the appearance and discomfort associated with the problem are anything but pleasant.

There are primarily two types of mange seen in dogs: sarcoptic mange and demodetic mange.  Sarcoptic mange is caused by a microscopic mite called Sarcotes scabiei. This mite burrows into the skin and feeds and reproduces in tiny tunnels made in the skin. This burrowing causes intense itching which generally results in hair loss and secondary bacterial infections. Sarcoptic mange especially affects the skin of the dog’s legs, belly, face and ears. Sometimes it can involve nearly the whole body. The mites are easily transferred from one dog to another (and from one animal to another).

The diagnosis can often be made from a skin scraping and by observing the mites under a microscope. But it is often made from looking at the signs, history of exposure, skin biopsy and/or response to treatment. Sarcoptic mange can be treated with anti-parasitic injectable medications and/or medicated baths. These are usually quite successful.

Demodetic mange is also caused by a microscopic mite called Demodex canis. Demodex mange mites can be "normal" skin inhabitants in dogs but the disease occurs when the mites are present in unusually high numbers, especially in young puppies and old or immuno-compromised dogs. The mites live in the hair follicles and typically cause areas of hair loss, especially around the eyes and muzzles and sometimes in patches on the body and feet. They can, however, affect the whole body. Demodex is not usually transferred from one dog to another, but puppies are commonly infested while nursing on an infested mother.

Diagnosis is made from a skin scraping and microscopic examination for the mites. Treatment is generally the same as for sarcoptic mange, but is not always successful, especially in older, less immuno-compromised patients. While most cases of demodetic mange are curable, some are only controlled and may require re-treatment. Demodex poses no threat to humans, but can be a very serious problem for affected dogs. The problem should be diagnosed by your veterinarian so appropriate therapy can be administered.

This information, prepared as a public service by the Rhode Island Veterinary Medical Association, answers problems Rhode Island veterinarians currently are seeing in their practices, as well as new developments in animal care.