Mange in Dogs and Cats

Laurie Anne Walden, DVM

Hair loss caused by demodectic mange in a dog. Public domain image.

Mange is skin disease caused by infection with mange mites. These tiny parasites cause skin inflammation, hair loss, and (sometimes) itching. Some types of mange are contagious to people and other animals. Mange is much easier to treat than it once was; some prescription flea, tick, and heartworm products are also effective against mange mites.
 
Signs
Mange looks very similar to skin disease caused by allergies, fleas, bacterial infections, or yeast infections. Animals with mange often have bacterial or yeast skin infections at the same time. The signs of mange depend partly on the type of mange mite involved, but these are the most common:

• Patches of hair loss
• Reddened skin
• Scaly or crusty skin
• Oozing skin sores
• Itching

 
Diagnosis
Mange is diagnosed by using a microscope to look for mites in skin scrapes or other samples. Mange mites can be hard to find, so skin scrapes can have false-negative results. Blood tests for some types of mites are available.
 
Treatment
In most cases, mange is treated with prescription flea, tick, and heartworm preventives like moxidectin, selamectin, fluralaner, afoxolaner, and sarolaner. These medications are available as spot-on topical products, chewable tablets, or injections. Because these medications are so effective against mites, they are often begun when mange is suspected but mites aren’t found on skin scrapes. Older treatments include lime sulfur dips and amitraz dips (dogs only).
 
Types of Mange in Dogs
Sarcoptic Mange (Canine Scabies)
Sarcoptic mange, or scabies, is caused by Sarcoptes scabiei. These mites are highly contagious to humans and other animals. Scabies is very itchy. Affected dogs usually also have bacterial and yeast skin infections. If untreated, scabies can cause severe generalized infection. Because scabies is contagious, all dogs in the household need to be treated.
 
Demodectic Mange (Demodicosis)
Demodex mites (usually D canis) live in the hair follicles of almost all dogs and usually don’t cause a problem. These mites are transferred from mother dogs to newborn puppies, but they are not contagious to people or other animals. Although D canis mites are benign in most dogs, they can cause 3 types of mange.

• Localized demodicosis: a few isolated scaly hairless patches, usually on the face or front legs, most often in dogs younger than 1 year. About 90% of these cases get better with no treatment; about 10% progress to generalized demodicosis.
• Juvenile-onset generalized demodicosis: severe skin lesions affecting much of the body and the feet, usually along with signs of general illness (fever, loss of energy, etc), in dogs younger than 1 year. In puppies, generalized demodicosis is caused by a genetic defect of the immune system, so affected puppies should not be used for breeding.
• Adult-onset generalized demodicosis: the same type of skin lesions as the juvenile form but first appearing in dogs at least 1 year old. In adult dogs, generalized demodicosis is usually caused by cancer or another disease that suppresses the immune system.

 
Types of Mange in Cats
Notoedric Mange (Feline Scabies)
Scabies in cats is caused by Notoedres cati. As with scabies in dogs, this type of mange in cats is contagious and intensely itchy.
 
Demodectic Mange
Like dogs, cats normally carry Demodex mites without any problem. Two types of Demodex mites cause 2 different forms of demodectic mange in cats.

• D cati lives in the hair follicles (like D canis), is not contagious to other animals, and causes either localized or generalized skin disease. Mange caused by D cati usually means that the cat has an underlying disease suppressing the immune system.
• D gatoi lives on the surface of the skin and is contagious to other cats, so all cats in contact with the affected cat need to be treated.

 
Image source: https://commons.wikimedia.org/wiki/File:Dogmangeeee.jpg

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