The characteristic symptoms of a scabies infection include intense itching and superficial burrows. The burrow tracks are often linear, to the point that a neat "line" of four or more closely placed and equally developed mosquito-like "bites" is almost diagnostic of the disease. Because the host develops the symptoms as a reaction to the mites' presence over time, typically a delay of four to six weeks occurs between the onset of infestation and the onset of itching. Similarly, symptoms often persist for one to several weeks after successful eradication of the mites. As noted, those re-exposed to scabies after successful treatment may exhibit symptoms of the new infestation in a much shorter period—as little as one to four days.

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.

In the classic scenario, the itch is made worse by warmth, and is usually experienced as being worse at night, possibly because distractions are fewer. As a symptom, it is less common in the elderly.

Scaly foot causes lesions of the skin with dermatitis and thickening of the skin.

Commonly known as scaly face, scaly legs, or tassel foot, knemidocoptiasis affects primarily the face and legs of birds around the world worldwide and can be fatal.

Also called demodicosis or red mange, demodectic mange is caused by a sensitivity to and overpopulation of "Demodex canis".

The two types of demodectic mange are localized and generalized. Localized consists of four spots or less. It is not contagious to humans.

Arthur Stanley Hirst, a noted authority on Acari states "In typical cases of this complaint the mites are found in enormous numbers, but Friedrich Gmeiner and also Albert E. Mettam have shown that "D. canis" is not the actual cause of follicular mange, which is due to a bacterium "Staphylococcus epidermidis" or some allied form. The mite plays an important part in the disease, however, by preparing the ground for the invasion of the bacterium by dilating the follicles and sweat-glands, and possibly also carries and introduces the germ. Whilst the Acari remain in the follicles or sweat-glands some of the bacteria may penetrate more deeply and be conveyed from one point to another by the blood-stream." - ""Studies on Acari No. 1. The Genus Demodex, Owen""

A type of demodectic infection in humans is known, but is less commonly symptomatic. See "Demodex folliculorum".

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.

This disease in humans is usually caused by "Demodex folliculorum" (not the same species affecting dogs) and is usually called demodicosis which may have a rosacea-like appearance. Common symptoms include hair loss, itching and inflammation. An association with pityriasis 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 be a small pustules (pimples or pustules) at the exit of hair, placed on inflamed, congested skin. Demodicosis is accompanied by itching, swelling and erythema of the eyelid margins, the appearance of scales at the base of the eyelashes. Typically, patients complain of eyestrain. Characteristic of view of the affected century: plaque on the edge of the eyelids, eyelashes stuck together, surrounded by crusts as a clutch.

Infections on the body may give rise to typical enlarging raised red rings of ringworm. Infection on the skin of the feet may cause athlete's foot and in the groin, jock itch. Involvement of the nails is termed onychomycosis, and they may thicken, discolour, and finally crumble and fall off. They are common in most adult people, with up to 20% of the population having one of these infections at any given moment.

Animals such as dogs and cats can also be affected by ringworm, and the disease can be transmitted between animals and humans, making it a zoonotic disease.

Specific signs can be:

- red, scaly, itchy or raised patches

- patches may be redder on outside edges or resemble a ring

- patches that begin to ooze or develop blister

- bald patches may develop, when the scalp is affected

- nails may thicken, discolour or begin to crack

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

"Demodex" is a genus of mite in the family Demodicidae. "Demodex canis" occurs naturally in the hair follicles of most dogs in low numbers around the face and other areas of the body. In most dogs, these mites never cause problems. However, in certain situations, such as an underdeveloped or impaired immune system, intense stress, or malnutrition, the mites can reproduce rapidly, causing symptoms in sensitive dogs that range from mild irritation and hair loss on a small patch of skin to severe and widespread inflammation, secondary infection, and in rare cases can be a life-threatening condition. Small patches of demodicosis often correct themselves over time as the dog's immune system matures, although treatment is usually recommended.

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.

The most common term for the infection, "ringworm", is a misnomer, since the condition is caused by fungi of several different species and not by parasitic worms.

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.

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.

There are several complications with the terminology:

Acariasis is a term for a rash, caused by mites, sometimes with a papillae (pruritic dermatitis), and usually accompanied by severe itching sensations. An example of such an infection is scabies.

The closely related term, mange, is commonly used with domestic animals (pets) and also livestock and wild mammals, whenever hair-loss is involved. "Sarcoptes" and "Demodex" species are involved in mange, but both of these genera are also involved in human skin diseases (by convention only, not called mange). "Sarcoptes" in humans is especially severe symptomatically, and causes the condition scabies noted above.

Another genus of mite which causing itching but rarely causes hair loss because it burrows only at the keratin level, is "Cheyletiella." Various species of this genus of mite also affect a wide variety of mammals, including humans.

Mite infestation sometimes implies an ectoparasitic, cutaneous condition such as dermatitis. However, it is possible for mites to invade the gastrointestinal and urinary tracts.

MeSH uses the term "Mite Infestations" as pertaining to Acariformes. However, mites not in this grouping can be associated with human disease. (See "Classification", below.)

The term Acari refers to ticks and mites together, which can cause ambiguity. (Mites are a paraphyletic grouping).

Mites can be associated with disease in at least three different ways: (1) cutaneous dermatitis, (2) production of allergin, and (3) as a vector for parasitic diseases. The language used to describe mite infestation often does not distinguish among these.

Physiological reactions to "Toxocara" infection depend on the host’s immune response and the parasitic load. Most cases of "Toxocara" infection are asymptomatic, especially in adults. When symptoms do occur, they are the result of migration of second stage "Toxocara" larvae through the body.

Covert toxocariasis is the least serious of the three syndromes and is believed to be due to chronic exposure. Signs and symptoms of covert toxocariasis are coughing, fever, abdominal pain, headaches, and changes in behavior and ability to sleep. Upon medical examination, wheezing, hepatomegaly, and lymphadenitis are often noted.

High parasitic loads or repeated infection can lead to visceral larva migrans (VLM). VLM is primarily diagnosed in young children, because they are more prone to exposure and ingestion of infective eggs. "Toxocara" infection commonly resolves itself within weeks, but chronic eosinophilia may result. In VLM, larvae migration incites inflammation of internal organs and sometimes the central nervous system. Symptoms depend on the organ(s) affected. Patients can present with pallor, fatigue, weight loss, anorexia, fever, headache, rash, cough, asthma, chest tightness, increased irritability, abdominal pain, nausea, and vomiting. Sometimes the subcutaneous migration tracks of the larvae can be seen. Patients are commonly diagnosed with pneumonia, bronchospasms, chronic pulmonary inflammation, hypereosinophilia, hepatomegaly, hypergammaglobulinaemia (IgM, IgG, and IgE classes), leucocytosis, and elevated anti-A and –B isohaemagglutinins. Severe cases have occurred in people who are hypersensitive to allergens; in rare cases, epilepsy, inflammation of the heart, pleural effusion, respiratory failure, and death have resulted from VLM.

Ocular larva migrans (OLM) is rare compared with VLM. A light "Toxocara" burden is thought to induce a low immune response, allowing a larva to enter the host’s eye. Although there have been cases of concurrent OLM and VLM, these are extremely exceptional. OLM often occurs in just one eye and from a single larva migrating into and encysting within the orbit. Loss of vision occurs over days or weeks. Other signs and symptoms are red eye, white pupil, fixed pupil, retinal fibrosis, retinal detachment, inflammation of the eye tissues, retinal granulomas, and strabismus. Ocular granulomas resulting from OLM are frequently misdiagnosed as retinoblastomas. "Toxocara" damage in the eye is permanent and can result in blindness.

A case study published in 2008 supported the hypothesis that eosinophilic cellulitis may also be caused by infection with "Toxocara". In this study, the adult patient presented with eosinophilic cellulitis, hepatosplenomegaly, anemia, and a positive ELISA for "T. cani"s.

Mud fever, also known as scratches or pastern dermatitis, is a group of diseases of horses causing irritation and dermatitis in the lower limbs of horses. Often caused by a mixture of bacteria, typically "Dermatophilus congolensis", and "Staphylococcus spp", mud fever can also be caused by fungal organisms (dermatophytes). Photosensitization, chorioptic mange mites, contact dermatitis and other conditions also contribute to some cases. This condition is also known as "dew poisoning," "grease heel," or "greasy heel".

Mud fever affects most horses and ponies during winter and early spring, resulting in painful sores and scabs, which in severe cases can make a horse lame. Mud fever most commonly affects the pastern and heel area but can also affect the upper leg, the belly, and in some cases the neck area (also known as Rain Scald). Non-pigmented skin tends to be more severely affected.

Toxocariasis is an illness of humans caused by larvae (immature worms) of either the dog roundworm ("Toxocara canis"), the cat roundworm ("Toxocara cati") or the fox roundworm ("Toxocara canis"). Toxocariasis is often called visceral larva migrans (VLM). Depending on geographic location, degree of eosinophilia, eye and/or pulmonary signs the terms ocular larva migrans (OLM), Weingarten's disease, Frimodt-Møller's syndrome, and eosinophilic pseudoleukemia are applied to toxocariasis. Other terms sometimes or rarely used include nematode ophthalmitis, toxocaral disease, toxocarose, and covert toxocariasis. This zoonotic, helminthic infection is a rare cause of blindness and may provoke rheumatic, neurologic, or asthmatic symptoms. Humans normally become infected by ingestion of embryonated eggs (each containing a fully developed larva, L2) from contaminated sources (soil, undercooked meat, fresh or unwashed vegetables.).

"Toxocara canis" and "Toxocara cati" are perhaps the most ubiquitous gastrointestinal worms (helminths) of domestic dogs and cats and foxes. There are many 'accidental' or paratenic hosts including humans, birds, pigs, rodents, goats, monkeys, and rabbits. In paratenic hosts the larvae never mature and remain at the L2 stage.

There are three main syndromes: "visceral larva migrans" (VLM), which encompasses diseases associated with major organs; "covert toxocariasis", which is a milder version of VLM; and "ocular larva migrans" (OLM), in which pathological effects on the host are restricted to the eye and the optic nerve.

A hot spot, or "acute moist dermatitis", is an acutely inflamed and infected area of skin irritation created and made worse by a dog licking and biting at itself. A hot spot can manifest and spread rapidly in a matter of hours as secondary Staphylococcus infection causes the top layers of the skin to break down and as pus becomes trapped in the hair. Hot spots can be treated with corticosteroid medications and oral as well as topical antibiotic application, as well as clipping hair from around the lesion. Underlying inciting causes include flea allergy dermatitis, ear disease or other allergic skin diseases. Dogs with thick undercoat are most subject to getting hot spots.

Mud fever is a chronic but progressive dermatitis. It affects all breeds of horses, but it is most common in heavy draft horses like the Clydesdales. It often starts as a small red ulceration of the skin in the plantar pastern region of the legs. The lesions then grow and develop scaling with the formation of a crust, hair loss, edema, oozing and the release of a malodorous exudate. Skin fissures and papillomatous lesions can develop in chronic cases.

Bullous impetigo, mainly seen in children younger than 2 years, involves painless, fluid-filled blisters, mostly on the arms, legs, and trunk, surrounded by red and itchy (but not sore) skin. The blisters may be large or small. After they break, they form yellow scabs.

This most common form of impetigo, also called nonbullous impetigo, most often begins as a red sore near the nose or mouth which soon breaks, leaking pus or fluid, and forms a honey-colored scab, followed by a red mark which heals without leaving a scar. Sores are not painful, but they may be itchy. Lymph nodes in the affected area may be swollen, but fever is rare. Touching or scratching the sores may easily spread the infection to other parts of the body.

Skin ulcers with redness and scarring also may result from scratching or abrading the skin.

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.

Feline acne is a problem seen in cats primarily involving the formation of blackheads accompanied by inflammation on the cat's chin and surrounding areas that can cause lesions, alopecia, and crusty sores. In many cases symptoms are mild and the disease does not require treatment. Mild cases will look like the cat has dirt on its chin, but the dirt will not brush off. More severe cases, however, may respond slowly to treatment and seriously detract from the health and appearance of the cat. Feline acne can affect cats of any age, sex or breed, although Persian cats are also likely to develop acne on the face and in the skin folds. This problem can happen once, be reoccurring, or even persistent throughout the cat's life.

Sebaceous glands are skin glands that produce oil and are mostly found in the skin of the chin, at the base of the tail, and in the eyelids, lips, prepuce, and scrotum. They are connected to hair follicles. In acne, the follicles become clogged with black sebaceous material, forming comedones (also known as blackheads). Comedones can become irritated, swollen, infected, and ultimately pustules. These may elicit itching and discomfort due to swelling and bacterial growth inside infected glands. Cats may continue to scratch and reopen wounds, allowing bacterial infections to grow worse. Bacterial folliculitis occurs when follicules become infected with "Staphylococcus aureus", and commonly associated with moderate-to-severe feline acne. Secondary fungal infections (species "malassezia") may also occur.

Other conditions that can cause similar-appearing conditions include skin mites, ringworm, yeast infection, or autoimmune diseases such as eosinophilic granuloma complex ("rodent ulcers"). These can be ruled out by a simple biopsy of affected cells.

Feline acne is one of the top five most common skin conditions that veterinarians treat.

Cat skin disorders are among the most common health problems in cats.

Skin disorders in cats have many causes, and many of the common skin disorders that afflict people have a counterpart in cats. The condition of a cat's skin and coat can also be an important indicator of its general health. Skin disorders of cats vary from acute, self-limiting problems to chronic or long-lasting problems requiring life-time treatment. Cat skin disorders may be grouped into categories according to the causes.

Although the exact cause of feline acne is unknown, some causes include:

- Hyperactive sebaceous glands

- Poor hygiene

- Stress

- Developing secondary to fungal, viral, and bacterial infections

- Reaction to medication

- Drinking from plastic containers to which the cat is allergic

- Demodicosis or mange, causing itchiness and hair loss

- Suppressed immune system

- Hair follicles that don't function properly

- Rubbing the chin (to display affection or mark territory) on non-sanitized household items

- Hormonal imbalance

- Contracting the infection from other cats in the same household