Demodicosis , also called Demodex folliculitis in humans and demodectic mange () or red mange in animals, is caused by a sensitivity to and overpopulation of '' Demodex spp.'' as the host's immune system is unable to keep the mites under control. '' Demodex'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Demodecidae. The mites are specific to their hosts, and each mammal species is host to one or two unique species of ''Demodex'' mites. Therefore, demodicosis cannot be transferred across species and has no zoonotic potential.

Signs and symptoms

Humans

Demodicosis in

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s is usually caused by '' Demodex folliculorum'' and may have a

rosacea Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarg ...

-like appearance. Common symptoms include

hair loss Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scar ...

, itching, and

inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

. An association with

pityriasis Pityriasis commonly refers to flaking (or scaling) of the skin. The word comes from the Greek πίτυρον "bran". Classification Types include: * Pityriasis alba * Pityriasis lichenoides chronica * Pityriasis lichenoides et varioliformis acu ...

folliculorum has also been described. Demodicosis is most often seen in folliculitis (inflammation of the hair follicles of the skin). Depending on the location, it may result in small pustules (pimples) at the base of a hair shaft on inflamed, congested skin. Demodicosis may also cause itching, swelling, and

erythema Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...

of the eyelid margins. Scales at the base of the eyelashes may develop. Typically, patients complain of eyestrain.

Dogs

Minor cases of demodectic mange usually do not cause much itching but might cause pustules, redness, scaling, leathery skin, hair loss, skin that is warm to the touch, or any combination of these. It most commonly appears first on the face, around the eyes, or at the corners of the mouth, and on the forelimbs and paws. It may be misdiagnosed as a "hot spot" or other skin ailment. In the more severe form, hair loss can occur in patches all over the body and might be accompanied by crusting, pain, enlarged lymph nodes, and deep skin infections. Typically, animals become infected through nursing from their mother. The transmission of these mites from mother to pup is ''normal'' (which is why the mites are normal inhabitants of the dog's skin), but some individuals are sensitive to the mites due to a cellular immune deficiency, underlying disease, stress, or malnutrition,Ectoparasites - Demodex (Mange Mite)
Companion Animal Parasite Control (March 2013). which can lead to the development of clinical demodectic mange. Some breeds appear to have an increased risk of mild cases as young dogs, including the

Afghan Hound The Afghan Hound is a hound that is distinguished by its thick, fine, silky coat and its tail with a ring curl at the end. The breed is selectively bred for its unique features in the cold mountains of Afghanistan. Its local name is ( ps, تاژ ...

American Staffordshire Terrier The American Staffordshire Terrier, also known as the AmStaff or American Staffy is a medium-sized, short-coated American dog breed. The height of an American Staffordshire Bull Terrier is tall and weighs between . The American Kennel Club (AKC) ...

Boston Terrier The Boston Terrier is a breed of dog originating in the United States of America. This "American Gentleman" was accepted in 1893 by the American Kennel Club as a non-sporting breed. Color and markings are important when distinguishing this breed f ...

, Boxer,

Chihuahua Chihuahua may refer to: Places * Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state **Chihuahua Mu ...

Chow Chow The Chow Chow is a spitz-type of dog breed originally from northern China. The Chow Chow is a sturdily built dog, square in profile, with a broad skull and small, triangular, erect ears with rounded tips. The breed is known for a very dense ...

, Shar-Pei,

Collie Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Man ...

, Dalmatian, Doberman Pinscher,

Bulldog The Bulldog is a British breed of dog of mastiff type. It may also be known as the English Bulldog or British Bulldog. It is of medium size, a muscular, hefty dog with a wrinkled face and a distinctive pushed-in nose.French Bulldog,

English Bull Terrier The Bull Terrier is a breed of dog in the terrier family. There is also a miniature version of this breed which is officially known as the Miniature Bull Terrier. Appearance The Bull Terrier's most recognizable feature is its head, described ...

, Miniature Bull Terrier,

German Shepherd The German Shepherd or Alsatian is a German breed of working dog of medium to large size. The breed was developed by Max von Stephanitz using various traditional German herding dogs from 1899. It was originally bred as a herding dog, for ...

, Great Dane, Old English Sheepdog,

American Pit Bull Terrier The American Pit Bull Terrier (APBT) is a dog breed recognized by the United Kennel Club (UKC) and the American Dog Breeders Association (ADBA), but not the American Kennel Club (AKC). It is a medium-sized, short-haired dog, of a solid build ...

, West Highland White Terrier,

Rat Terrier The Rat Terrier is an American dog breed with a background as a farm dog and hunting companion. They share much ancestry with the small hunting dogs known as feists. Common throughout family farms in the 1920s and 1930s, they are now recogniz ...

, Yorkshire Terrier,

Dachshund The dachshund ( or ; German: " badger dog"), also known as the wiener dog, badger dog, and sausage dog, is a short-legged, long-bodied, hound-type dog breed. The dog may be smooth-haired, wire-haired, or long-haired, and comes in a variety o ...

, and Pug.

Cats

There are two types of demodectic mange in cats. ''Demodex cati'' causes follicular mange, similar to that seen in dogs, though it is much less common. ''Demodex gatoi'' is a more superficial form of mange, causes an itchy skin condition, and is contagious amongst cats.

Other

Demodectic mange also occurs in other domestic and wild animals, including captive pandas.

Diagnosis

For demodectic mange, properly performed deep skin scrapings generally allow the veterinarian to identify the microscopic mites. Acetate tape impression with squeezing has recently found to be a more sensitive method to identify mites. It was originally thought that because the mite is a normal inhabitant of the dog's skin, the presence of the mites does not conclusively mean the dog has demodicosis. Recent research, however, found that the demodex mite is rarely found on clinically normal dogs, meaning that the presence of any number of mites in a sample is very likely to be significant. In breeds such as the West Highland White Terrier, relatively minor skin irritation which would otherwise be considered allergy should be carefully scraped because of the predilection of these dogs to demodectic mange. Skin scrapings may be used to follow the progress of treatment in demodectic mange. Alternatively, plasma levels of zinc and copper have been seen to be decreased in dogs with demodicosis. This may be due to inflammation involved in the immune response of demodicosis which can lead to oxidative stress, resulting in dogs with demodicosis to exhibit higher levels of

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubrica ...

productivity. The catalases involved in the antioxidant pathway require the trace minerals zinc and copper. Dogs with demodicosis show a decrease in plasma copper and zinc levels due to the increased demand for antioxidant activity. Therefore, this may be considered as a potential marker for demodicosis.

Treatment

Dogs

Localized demodectic mange is considered a common puppyhood ailment, with roughly 90% of cases resolving on their own with no treatment. Minor, localized cases should be left to resolve on their own to prevent masking of the more severe generalized form. If treatment is deemed necessary, Goodwinol, a rotenone-based insecticide ointment, is often prescribed, but it can be irritating to the skin. Demodectic mange with secondary infection is treated with

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s and medicated shampoos. For more severe generalized cases, Amitraz is a parasiticidal dip that is licensed for use in many countries (the only FDA approved treatment in the USA) for treating canine demodicosis. It is applied weekly or biweekly for several weeks, until no mites can be detected by skin scrapings. Demodectic mange in dogs can also be managed with avermectins, although there are few countries which license these drugs, which are given by mouth daily, for this use.

Ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat i ...

is used most frequently;

collie Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Man ...

-like herding breeds often do not tolerate this drug due to a defect in the

blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of the central nervous system where ne ...

, though not all of them have this defect. Other avermectin drugs that can be used include doramectin and

milbemycin The milbemycins are a group of macrolides chemically related to the avermectins and were first isolated in 1972 from '' Streptomyces hygroscopicus''. They are used in veterinary medicine as antiparasitic agents against worms, ticks and fleas.

. Recent results suggest that the isoxazolines afoxolaner and

fluralaner Fluralaner (International nonproprietary name, INN) is a systemic insecticide and acaricide that is administered orally or topically. The U.S. Food and Drug Administration (FDA) approved it under the trade name Bravecto for flea treatment in dogs ...

, given orally, are effective in treating dogs with generalized demodicosis. Because of the possibility of the immune deficiency being an inherited trait, many veterinarians believe that all puppies with generalized demodex should be spayed or neutered and not reproduce. Females with generalized demodex should be spayed because the stress of the estrus cycle will often bring on a fresh wave of clinical signs.

Cats

Cats with ''Demodex gatoi'' must be treated with weekly or bi-weekly sulfurated lime rinses. ''Demodex cati'' are treated similarly to canine demodicosis. With veterinary guidance, localized demodectic mange can also be treated with a topical keratolytic and antibacterial agent, followed by a lime sulfur dip or a local application of Rotenone. Ivermectin may also be used. Generalized demodectic mange in cats is more difficult to treat. There are shampoos available that can help to clear dead skin, kill mites and treat bacterial infections. Treatment is in most cases prolonged with multiple applications.

References

External links

{{Mite-related diseases and infestations Dog diseases Arthropod infestations Parasitic infestations, stings, and bites of the skin