Mange

Mange

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Mange is the common name for a class of persistent contagious skin diseases caused by parasitic mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

s. Since mites also infect plants, birds, and reptiles, the term "mange," suggesting poor condition of the hairy coat due to the infection, is sometimes reserved only for pathological mite-infestation of non-human mammals. Thus, mange is a term used to describe mite-associated skin disease in domestic animals (cats and dogs), in livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...

 (such as sheep scab), and in wild animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s (for example, coyotes, cougars, and bears). Since mites belong to the arachnid subclass Acari (also called Acarina), another term used to describe mite infestation is acariasis
Acariasis
-Terminology:There are several complications with the terminology:Acariasis is a term for a rash, caused by mites, sometimes with a papillae , and usually accompanied by severe itching sensations....

.

Mammalian parasitic mites that cause mange embed themselves either in skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 or hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

s, depending upon their genus. Sarcoptes
Sarcoptes
Sarcoptes is a genus of mite.In some contexts, the types are all considered subordinate to Sarcoptes scabiei.* Sarcoptes scabiei var. bovis* Sarcoptes scabiei var. canis* Sarcoptes scabiei var. caprae* Sarcoptes scabiei var. equi...

 spp.
burrow into skin, while Demodex spp. live in follicles.

In humans, these two types of mite infections, which would otherwise be known as "mange" in furry mammals, are instead known (respectively) as scabies
Scabies
Scabies , known colloquially as the seven-year itch, is a contagious skin infection that occurs among humans and other animals. It is caused by a tiny and usually not directly visible parasite, the mite Sarcoptes scabiei, which burrows under the host's skin, causing intense allergic itching...

 and demodicosis
Demodicosis
Demodicosis, also called demodectic mange or red mange, is caused by a sensitivity to and overpopulation of Demodex canis as the animal's immune system is unable to keep the mites under control....

. However, the mites that cause these diseases in humans are closely related to those that cause the mange in other mammals.

Types of mange


Two types of pet-associated mites afflict dogs and cats with a type of hair-losing dermatitis, and each type has characteristic symptoms.

Demodectic mange in dogs


Also called demodicosis or Red Mange, demodectic mange is caused by a sensitivity to and overpopulation of Demodex canis
Demodex mite
Demodex is a genus of tiny parasitic mites that live in or near hair follicles of mammals. About 65 species of Demodex are known; they are among the smallest of arthropods. Two species living on humans have been identified: Demodex folliculorum and Demodex brevis, both frequently referred to as...

if the animal's immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

 is unable to keep the mites under control.
There are two types of demodectic mange: localized and generalized. Localized consists of 4 spots or less. Most dogs are immune to demodectic mange, however dogs with compromised immune systems and the elderly are at a higher risk. It is not contagious to humans.

A type of demodetic infection in humans in known, but is less commonly symptomatic. See Demodex folliculorum
Demodex folliculorum
Demodex folliculorum is a species of face mite. D. folliculorum is one of the parasitic face mites that occur on people . Demodex derives from the Greek roots, demos- fat, and dex- worm. When large numbers of D...

.

Sarcoptic mange





Also known as canine scabies
Scabies
Scabies , known colloquially as the seven-year itch, is a contagious skin infection that occurs among humans and other animals. It is caused by a tiny and usually not directly visible parasite, the mite Sarcoptes scabiei, which burrows under the host's skin, causing intense allergic itching...

, sarcoptic mange is a highly contagious infestation of Sarcoptes scabiei canis, a burrowing mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

. The canine sarcoptic mite can also infest cats, pigs, horses, sheep and various other species. The human analog of burrowing mite infection, due to a closely related species, is called scabies
Scabies
Scabies , known colloquially as the seven-year itch, is a contagious skin infection that occurs among humans and other animals. It is caused by a tiny and usually not directly visible parasite, the mite Sarcoptes scabiei, which burrows under the host's skin, causing intense allergic itching...

 (the "seven year itch").

All these burrowing mites are in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Sarcoptidae
Sarcoptidae
Sarcoptidae is a family of mites, of which the most prominent are in the Genus Sarcoptes. Sarcoptic mange is caused by digging mites in that genus....

. They dig into and through the skin, causing intense itching from an allergic reaction to the mite, and crusting that can quickly become infected
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

. Hair loss and crusting frequently appear first on elbows and ears. Skin damage can occur from the dog's intense scratching and biting. Secondary skin infection is also common. Dogs with chronic sarcoptic mange are often in poor condition, and in both animals and humans immune suppression from starvation or any other disease causes this type of mange to develop into a highly crusted form in which the burde of mites is far higher than in healthy specimens.

Treatment


Dogs affected with demodectic mange do not need to be isolated from other dogs. Demodectic mange is generally only contagious from mother to pup during suckling. Demodectic mange is not contagious after weaning. Many puppies will grow out of demodectic mange as their immune systems mature. Demodectic mange can recur if the immune system is compromised such as after steroid treatment or other immune-compromising illness. Treatment with ivermectin is often prescribed by vets along with skin scrapings. Ivermectin is often continued until two negative skin scrapings are achieved.

In cases of sarcoptic mange, affected dogs need to be isolated from other dogs and their bedding, and places they have occupied must be thoroughly cleaned. Other dogs in contact with a diagnosed case should be evaluated and treated.

There are a number of parasitical treatments useful in treating canine scabies. Sulfurated lime
Lime sulfur
In horticulture, lime sulfur is a mixture of calcium polysulfides formed by reacting calcium hydroxide with sulfur, used in pest control. It can be prepared by boiling calcium hydroxide and sulfur together with a small amount of surfactant...

 rinses applied weekly or bi-weekly are effective (warning: the concentrated form for use on plants as a fungicide must be diluted 1:16 or 1:32 for use on animal skin). Selamectin
Selamectin
Selamectin is a topical parasiticide and antihelminthic used on dogs and cats, distributed by Pfizer. It prevents heartworms, fleas, ear mites, sarcoptic mange , and certain types of ticks in dogs, and prevents heartworms, fleas, ear mites, hookworms, and roundworms in cats...

 is licensed for treatment by veterinary prescription in several countries; it is applied as a drip-on directly to the skin. Ivermectin is effective and can be given by mouth for two to four weekly treatments; this drug is not safe to use on some collie-like herding dog
Herding dog
A herding dog, also known as a stock dog or working dog, is a type of pastoral dog that either has been trained in herding or belongs to breeds developed for herding...

s, however, due to possible homozygous MDR1 (P-glycoprotein
P-glycoprotein
P-glycoprotein 1 also known as multidrug resistance protein 1 or ATP-binding cassette sub-family B member 1 or cluster of differentiation 243 is a glycoprotein that in humans is encoded by the ABCB1 gene...

) mutations that increase its toxicity. Ivermectin injections are also effective and given in either weekly or every two weeks in one to four doses. Topical 0.01% ivermectin (Acarexx) has been reported to be effective in humans and many types of animals (especially in ear mite
Ear mite
Ear mites are mites that live in the ears of animals. The most commonly seen species is Otodectes cynotis .-Contagion:...

 infections where the animal cannot lick the treated area), and is so poorly absorbed that systemic toxicity is less likely in these sites. Nevertheless, topical ivermectin has not been well enough tested to be approved for this use in dogs, and is theoretically much more dangerous in zones where the animal can potentially lick the treated area.

Similar treatments are used in cats with mange, but permethrin
Permethrin
Permethrin is a common synthetic chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to...

, which can be used in both dogs and humans with this condition, cannot be used in cats. The differences in cat and dog treatment are not due to differences in the mites so much as the mitocides which are poisonous to the host.

For treatment of sarcoptic infection in humans, see scabies
Scabies
Scabies , known colloquially as the seven-year itch, is a contagious skin infection that occurs among humans and other animals. It is caused by a tiny and usually not directly visible parasite, the mite Sarcoptes scabiei, which burrows under the host's skin, causing intense allergic itching...

. For demodetic infection in humans, which is not as severe as it is in animals with thicker coats (such as dogs), see Demodex folliculorum
Demodex folliculorum
Demodex folliculorum is a species of face mite. D. folliculorum is one of the parasitic face mites that occur on people . Demodex derives from the Greek roots, demos- fat, and dex- worm. When large numbers of D...

.

Diagnosis


Veterinarian
Veterinarian
A veterinary physician, colloquially called a vet, shortened from veterinarian or veterinary surgeon , is a professional who treats disease, disorder and injury in animals....

s usually attempt diagnosis with skin scrapings from multiple areas, which are then examined under a microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...

 for mites. Sarcoptes, because they may be present in relatively low numbers, and because they are often removed by dogs chewing at themselves, may be difficult to demonstrate. As a result, diagnosis in Sarcoptic mange is often based on symptoms rather than actual confirmation of the presence of mites. A common and simple way of determining if a dog has mange is if it displays what is called a "Pedal-Pinna reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

", which is when the dog moves one of its hind legs in a scratching motion as the ear is being manipulated and scratched gently by the examiner; because the mites proliferate on the ear margins in nearly all cases at some point, this method works over 95% of the time. It is helpful in cases where all symptoms of mange are present but no mites are observed with a microscope. In some countries, a serologic test is available that may be useful in diagnosis.

See also


  • Cheyletiellosis
    Cheyletiellosis
    Cheyletiella is a genus of mites that live on the skin surface of dogs, cats, rabbits, and humans.The adult mites are about 0.385 millimeters long, have eight legs that have combs instead of claws, and have palpi that end in prominent hooks. They do not burrow into the skin but live in the keratin...

    A genus of mite that causes dermatitis and itching in many groups of mammals, including pets and humans, but rarely causes hair loss, and therefore is not usually considered clinically to cause "mange"

Further reading