Scabies is contagious and can be contracted through prolonged physical contact with an infested person. This includes sexual intercourse, although a majority of cases are acquired through other forms of skin-to-skin contact. Less commonly, scabies infestation can happen through the sharing of clothes, towels, and bedding, but this is not a major mode of transmission; individual mites can only survive for two to three days, at most, away from human skin at room temperature. As with lice, a latex condom is ineffective against scabies transmission during intercourse, because mites typically migrate from one individual to the next at sites other than the sex organs.

Healthcare workers are at risk of contracting scabies from patients, because they may be in extended contact with them.

Scabies is endemic in many developing countries, where it tends to be particularly problematic in rural and remote areas. In such settings, community-wide control strategies are required to reduce the rate of disease, as treatment of only individuals is ineffective due to the high rate of reinfection. Large-scale mass drug administration strategies may be required where coordinated interventions aim to treat whole communities in one concerted effort. Although such strategies have shown to be able to reduce the burden of scabies in these kinds of communities, debate remains about the best strategy to adopt, including the choice of drug.

The resources required to implement such large-scale interventions in a cost-effective and sustainable way are significant. Furthermore, since endemic scabies is largely restricted to poor and remote areas, it is a public health issue that has not attracted much attention from policy makers and international donors.

Minor cases of demodectic mange usually do not cause much itching but might cause pustules on the dog's skin, redness, scaling, leathery, hair loss, 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. 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.

Demodectic mange is transmitted from host to host through direct contact. Typically animals become infected through nursing from their mother. Demodex mites are host-adapted; there is no zoonotic potential in either canine or feline demodicosis. These mites ("Demodex canis") thrive only on their specific hosts (dogs). 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, 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, American Staffordshire Terrier, Boston Terrier, Boxer, Chihuahua, Chow Chow, Shar Pei, Collie, Dalmatian, Doberman Pinscher, Bulldog, French Bulldog, English Bull Terrier, Miniature Bull Terrier, German Shepherd Dog, Great Dane, Old English Sheepdog, American Pit Bull Terrier, West Highland White Terrier, Rat Terrier, Yorkshire Terrier, dachshund and Pug.

Demodectic mange also occurs in other domestic and wild animals including captive pandas and in China. The mites are specific to their hosts, and each mammal species is host to one or two unique species of Demodex mites. 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.

Mange is a class of skin diseases caused by parasitic mites. 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 nonhuman mammals. Thus, mange includes mite-associated skin disease in domestic animals (cats and dogs), in livestock (such as sheep scab), and in wild animals (for example, coyotes, cougars, and bears). Since mites belong to the arachnid subclass Acari (also called Acarina), another term for mite infestation is acariasis.

Parasitic mites that cause mange in mammals embed themselves either in skin or hair follicles in the animal, depending upon their genus. "Sarcoptes" 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 and demodicosis.

Scaly foot, otherwise known as knemidocoptiasis, is caused by burrowing mites in the genus "Knemidocoptes". The condition can be compared with sarcoptic mange in mammals, but does not seem to cause the same level of itching. The birds chiefly affected are galliformes (chickens and turkeys), passerines (finches, canaries, sparrows, robins, wrens), and psittacine birds (parrots, macaws, parakeets, budgerigars). The condition sometimes additionally affects piciformes (woodpeckers, toucans) and anseriformes ducks, geese, swans), raptors and other birds. The two species of mite most often implicated are "K. jamaicensis" and "K. intermedius". Other related species of mite affect feather follicles and cause depluming. The mites are mostly transmitted by prolonged direct contact, particularly from parent bird to unfledged nestling.

Sarcoptic mange, also known as canine scabies, is a highly contagious infestation of "Sarcoptes scabiei canis", a burrowing mite. 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 (the "seven year itch").

All these burrowing mites are in the family Sarcoptidae. They dig into and through the skin, causing intense itching from an allergic reaction to the mite, and crusting that can quickly become infected. 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 burden of mites is far higher than in healthy specimens.

Scaly foot, or knemidocoptiasis is a bird ailment that is common among caged birds and also affects many other bird species. It is caused by mites in the genus "Knemidocoptes" which burrow into the bird's flesh. The tunnels made by the mites within the skin cause dermatitis and scaly lesions. Scaly face is caused by the same mite responsible for scaly foot and other related mites cause depluming. The condition is transmitted from one bird to another by direct prolonged contact.

Demodex mite bite is a cutaneous condition caused by infestation by "Demodex folliculorum".

The rabbit ear mite, "Psoroptes cuniculi", is larger than "Otodectes cynotis". It causes thick firm debris to form in the ear canal, and can eventually migrate to the skin of the outer ear and face. Symptoms include scratching and shaking of the head. Treatment includes topical selamectin, or injections of ivermectin and frequent cleanings of the rabbit's environment.

Ear mites are mites that live in the ears of animals and humans. The most commonly seen species in veterinary medicine is "Otodectes cynotis" (Gk. oto=ear, dectes=biter, cynotis=of the dog). This species, despite its name, is also responsible for 90% of ear mite infections in cats.

In veterinary practice, ear mite infections in dogs and cats may present as a disease that causes intense itching in one or both ears, which in turn triggers scratching at the affected ear. An unusually dark colored ear wax (cerumen) may also be produced. Cats, as well as dogs with erect ears that have control over ear direction, may be seen with one or both ear pinnas held at an odd or flattened angle.

The most common lesion associated with ear mites is an open or crusted ("scabbed") skin wound at the back or base of the ear, caused by abrasion of the skin by hind limb claws, as the ear has been scratched in an attempt to relieve the itching. This lesion often becomes secondarily infected and crusted from ordinary skin bacteria, so that the common presentation of ear mites is such a wound appearing on the back or base of one or both ears. This is accompanied by the Pinnal-Pedal Reflex that appears as reflex scratching motions of the hind limb when the ear is manipulated (this test is positive as well in other mite infections of the outside and rim of the ear pinnas in mange). When the ear mite infection is treated, such wounds resolve spontaneously, and this resolution may be speeded with application of topical antibiotics.

The most common ear mite (as well as mange mite) treatments currently use the antiparasitics ivermectin and selamectin, usually as topical preparations. Ivermectin is available as a direct water-based liquid that is squeezed into the ear canal and massaged at the base of the ear to distribute the medication. Selamectin is available as a once-a-month preparation that can be applied to the animal's skin, which prevents mite infestation over that time.

Bed bug bites are caused by bed bugs primarily of two species "Cimex lectularius" (the common bed bug) and "Cimex hemipterus". Infestation is rarely due to a lack of hygiene. These insects feed exclusively on blood and may survive a year without eating. They are attracted by body warmth and carbon dioxide. Transfer to new places is usually in the personal effects of the human they feed upon.

Dwellings can become infested with bed bugs in a variety of ways, such as:

- Bugs and eggs inadvertently brought in from other infested dwellings on a visiting person's clothing or luggage;

- Infested items (such as furniture especially beds or couches, clothing, or backpacks) brought in a home or business;

- Nearby dwellings or infested items, if easy routes are available for travel, e.g. through ducts or false ceilings;

- Wild animals (such as bats or birds) that may also harbour bed bugs or related species such as the bat bug;

- People visiting an infested area (e.g. dwelling, means of transport, entertainment venue, or lodging) and carrying the bugs to another area on their clothing, luggage, or bodies. Bedbugs are increasingly found in air travel.

- Though bed bugs will feed on pets, they do not live or travel on the skin of their hosts, and pets are not believed a factor in their spread.

Most of the mites which cause this affliction to humans are from the order Acari, hence the name Acariasis. The entire taxonomic classification to order would be:

- Kingdom: Animalia

- Phylum: Arthropoda

- Subphylum: Chelicerata

- Class: Arachnida

- Order: Acari (At the order level, there is still substantial argument among researchers as to how to categorize Acari. Some call it a subclass, others a superorder, "Acarina".)

Specific species involved include:

- Acariformes

- Trombidiformes

- "Trombicula" species (trombiculosis or chiggers)

- "Demodex" species (Demodicosis)

- "Pyemotes tritici"

- "Cheyletiella"

- Sarcoptiformes

- "Sarcoptes scabiei" (Scabies)

- Parasitiformes

- "Dermanyssus gallinae"

- "Liponyssoides sanguineus"

- "Ornithonyssus bacoti", "Ornithonyssus bursa", "Ornithonyssus sylviarum"

- Another candidate is "Androlaelaps casalis". However, based on this mite's life style as a predator on other mite species (such as the previously-mentioned "Dermanyssus gallinae"), it is highly unlikely to be a cause of acariasis.

Some of these reflect reports existing of human infestation by mites previously believed not to prey on humans.

Atopy is a hereditary and chronic (lifelong) allergic skin disease. Signs usually begin between 6 months and 3 years of age, with some breeds of dog, such as the Golden Retriever showing signs at an earlier age. Dogs with atopic dermatitis are itchy, especially around the eyes, muzzle, ears and feet. In severe cases the irritation is generalised. If the allergens are seasonal, the signs of irritation are similarly seasonal. Many dogs with house dust mite allergy have perennial disease. Some of the allergens associated with atopy in dogs include pollens of trees, grasses and weeds, as well as molds and House dust mite. Ear and skin infections with the bacteria "Staphylococcus pseudintermedius" and the yeast "Malassezia pachydermatis" are common secondary to atopic dermatitis.

Food allergy can be associated with identical signs and some authorities consider food allergy to be a type of atopic dermatitis.

Diagnosis of atopic dermatitis is by elimination of other causes of irritation including fleas, scabies and other parasites such as Cheyletiella and lice. Food allergy can be identified through the use of elimination diet trials in which a novel or hydrolysed protein diet is used for a minimum of 6 weeks and allergies to aeroallergens can be identified using intradermal allergy testing and/or blood testing (allergen-specific IgE ELISA).

Treatment includes avoidance of the offending allergens if possible, but for most dogs this is not practical or effective. Other treatments modulate the adverse immune response to allergens and include antihistamines, steroids, ciclosporin and immunotherapy (a process in which allergens are injected to try to induce tolerance). In many cases shampoos, medicated wipes and ear cleaners are needed to try to prevent the return of infections.

New research into T-cell receptor peptides and their effects on dogs with severe, advanced atopic dermatitis are being investigated.

A number of other symptoms may occur from either the bite of the bed bugs or from their exposure. Anaphylaxis from the injection of serum and other nonspecific proteins has been rarely documented. Due to each bite taking a tiny amount of blood, chronic or severe infestation may lead to anemia. Bacterial skin infection may occur due to skin break down from scratching.

Systemic poisoning may occur if the bites are numerous. Exposure to bed bugs may trigger an asthma attack via the effects of airborne allergens although evidence of this association is limited. There is no evidence that bed bugs transmit infectious diseases even though they appear physically capable of carrying pathogens and this possibility has been investigated. The bite itself may be painful thus resulting in poor sleep and worse work performance.

Similar to humans, pets can also be bitten by bed bugs. The signs left by the bites are the same as in case of people and cause identical symptoms (skin irritation, scratching etc).

The exact causes of dyshidrosis are unknown. In 2013, a randomized, double-blind, placebo-controlled cross-over study by the University Medical Center Groningen reported that dyshydrosis outbreaks on the hands increased significantly among those allergic to house dust mites, following inhalation of house dust mite allergen.

Food allergens may be involved in certain cases. Cases studies have implicated a wide range of foods including tuna, tomato, pineapple, chocolate, coffee, and spices among others. A number of studies have implicated balsam of Peru.

Id reaction and irritant contact dermatitis are possible causes.

Chiggers are commonly found on the tip of blades of grasses to catch a host, so keeping grass short, and removing brush and wood debris where potential mite hosts may live, can limit their impact on an area. Sunlight that penetrates the grass will make the lawn drier and make it less favorable for chigger survival.

Chiggers seem to affect warm covered areas of the body more than drier areas. Thus, the bites are often clustered behind the knees, or beneath tight undergarments such as socks, underwear, or brassieres. Areas higher in the body (chest, back, waist-band, and under-arms) are affected more easily in small children than in adults, since children are shorter and are more likely than adults to come in contact with low-lying vegetation and dry grass where chiggers thrive. An exceptional case has been described in the eye, producing conjunctivitis.

Application of repellent to the shoes, lower trousers and skin is also useful. Because they are found in grass, staying on trails, roads, or paths can prevent contact. Dusting sulfur is used commercially for mite control and can be used to control chiggers in yards. The dusting of shoes, socks and trouser legs with sulfur can be highly effective in repelling chiggers.

Another good strategy is to recognize the chigger habitat to avoid exposure in the first place. Chiggers in North America thrive late in summer, in dry tall grasses and other thick, unshaded vegetation. Insect repellents containing one of the following active ingredients are recommended: DEET, catnip oil extract (nepetalactone), citronella oil or eucalyptus oil extract. However, in 1993 issue a study reported on tests of two commercial repellents: DEET and citrus oil: "All chiggers exposed on the filter papers treated with DEET died and did not move off the treated papers. None of the chiggers that were placed on papers treated with citrus oil were killed." It was concluded that DEET was more effective than citrus oil.

Chiggers can also be treated using common household vinegar (5% acetic acid).

Scaly leg is a disease of chickens and other birds. It is caused by a parasitic mite, "cnemidocoptes mutans". The mite burrows under the scales in the bird's legs, but may also infest other areas, such as the comb or wattles of chickens. The mite spends its entire lifecycle on the birds and is usually spread by direct contact.

Birds infested with scaly leg have raised or protruding scales, sometimes with a white crusty appearance. Scaly leg is irritating to the infected bird, and in extreme cases can result in lameness.

In domestic birds the disease may be treated by application of an oily substance such as petroleum jelly, vegetable oil, or a commercial chest rub, thus preventing the mites breathing. Alternatively an insecticide may be used to kill the mites – or the two methods may be combined. The loose crusty scales may also be removed by soaking the afflicted bird's legs in soapy water mixed with diluted ammonia, and the encrusted areas scrubbed gently with a soft brush. Complete removal may take multiple treatments. Dropped scales may remain infectious for up to a month, and so pen, perches, and nesting areas may also be treated, or birds may be moved to different housing for several weeks.

Pemphigus foliaceus is the most common autoimmune disease of the dog. Blisters in the epidermis rapidly break to form crusts and erosions most often affecting the face and ears initially, but in some cases spreading to include the whole body. The pawpads can be affected causing marked hyperkeratosis (thickening of the pads with scale). Other autoimmune diseases include bullous pemphigoid and epidermolysis bullosa acquisita.

Treatment of autoimmune skin conditions requires treatment to markedly reduce the abnormal immune response; steroids, azathoprine and other drugs are used as immunosuppressive agents.

Medical doctors and dermatologists can still misdiagnose this rash as many are unfamiliar with parasitism, not trained in it, or if they do consider it, cannot see the mites.

Different methods for detection are recognized for different acariasis infections. Human acariasis with mites can occur in the gastrointestinal tract, lungs, urinary tracts and other organs which not have been well-studied. For intestinal acariasis with symptoms such as abdominal pain, diarrhea, and phohemefecia (is this hemafecia?), human acariasis is diagnosed by detection of mites in stools. For pulmonary acariasis, the presence of mites in sputum is determined by identifying the presence and number of mites in the sputum of patients with respiratory symptoms. Both physical and chemical methods for liquefaction of sputum have been developed.

Trombiculosis, trombiculiasis, or trombiculidiasis is a rash caused by trombiculid mites which is often referred to as a chigger bite.

Eosinophilic folliculitis associated with HIV infection typically affects individuals with advanced HIV and low T helper cell counts. It affects both men and women as well as children with HIV and is found throughout the world.

EF may also affect individuals with hematologic disease such as leukemia and lymphoma. It may also affect otherwise normal infants in a self-limited form. HIV-negative individuals can also develop EF — this is more common in Japan.

Wheat warehouse itch is a cutaneous condition caused by a mite, "Cheyletus malaccensis".

Insect bites and stings occur when an insect is agitated and seeks to defend itself through its natural defense mechanisms, or when an insect seeks to feed off the bitten person. Some insects inject formic acid, which can cause an immediate skin reaction often resulting in redness and swelling in the injured area. Stings from fire ants, bees, wasps and hornets are usually painful, and may stimulate a dangerous allergic reaction called anaphylaxis for at-risk patients, and some wasps can also have a powerful bite along with a sting. Bites from mosquitoes and fleas are more likely to cause itching than pain.

The skin reaction to insect bites and stings usually lasts for up to a few days. However, in some cases the local reaction can last for up to two years. These bites are sometimes misdiagnosed as other types of benign or cancerous lesions.

The reaction to a sting is of three types. The normal reaction involves the area around the bite with redness, itchiness, and pain. A large local reaction occurs when the area of swelling is greater than 5 cm. Systemic reactions are when symptoms occur in areas besides that of the bites.

With insect stings a large local reaction may occur (an area of skin redness greater than 10 cm in size). It can last one to two days. It occurs in about 10% of those bitten.