The cat must have a supply of niacin, as cats cannot convert tryptophan into niacin like dogs. However, diets high in corn and low in protein can result in skin lesions and scaly, dry, greasy skin, with hair loss. Another B vitamin, biotin, if deficient causes hair loss around the eyes and face. A lack of B vitamins can be corrected by supplementing with a vitamin B complex, and brewers yeast.

Cats cannot synthesize vitamin A from plant beta-carotene, and therefore must be supplemented with retinol from meat. A deficiency in vitamin A will result in a poor coat, with hair loss, with scaly and thickened skin. However an excess of vitamin A, called hypervitaminosis A, can result from over feeding cod liver oil, and large amounts of liver. Signs of hypervitaminosis A are overly sensitive skin, and neck pain causing the cat to be unwilling to groom its self, resulting in a poor coat. Supplementing vitamin A with retinol to a deficient cat, and feeding a balanced diet to a cat with hypervitaminosis A will treat the underlying nutritional disorder.

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

Placing the cat's water in a shallow dish may prevent the chin from absorbing the bacteria in the water while the cat is drinking. If the cat is allergic to plastics or dyes, using a stainless-steel or glass dish is recommended . Cats may also have food allergies that make the development of acne more likely, so that switching kibble, or changing to a hydrolysed diet may be effective. Maintaining good hygiene and grooming habits make the development of feline acne less likely. Washing and exfoliating the chin with a gentle benzoyl-peroxide solution also may be preventive of further outbreaks.

Advice often given includes:

- Avoid sharing clothing, sports equipment, towels, or sheets.

- Wash clothes in hot water with fungicidal soap after suspected exposure to ringworm.

- Avoid walking barefoot; instead wear appropriate protective shoes in locker rooms and sandals at the beach.

- Avoid touching pets with bald spots, as they are often carriers of the fungus.

Gardasil 6 is an HPV vaccine aimed at preventing cervical cancers and genital warts. Gardasil is designed to prevent infection with HPV types 16, 18, 6, and 11. HPV types 16 and 18 currently cause about 70% of cervical cancer cases, and also cause some vulvar, vaginal, penile and anal cancers. HPV types 6 and 11 are responsible for 90% of documented cases of genital warts.

Gardasil 9, approved in 2014 protects against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58.

HPV vaccines do not currently protect against the virus strains responsible for plantar warts (verrucas).

The cat should be taken to a veterinarian. The most suspected cause of skin problems in cats will be fleas. Other causes of over-grooming are not as easily ascertained. As household antiseptics are known to be toxic to cats, veterinary antiseptics for cats can be used to treat open sores, if they do occur. Sores can also be treated with cream, oral or injected anti-inflammatories, however if the problem continues to recur it may be more cost effective to subject the cat to laboratory testing early on. It may be difficult to keep a clean dressing on a cat's belly, and an anti-lick collar is adequate to let the wound heal. If an anti lick collar is used, a soft anti-lick collar is less cumbersome, although they are less durable. If the cat wears a plastic anti-lick collar, it may use the edge of the collar to grind against existing wounds, making them worse. A soft anti lick collar will become less effective as it is kicked out of the shape by the cat's hind leg, and will need prompt replacement. The cat can sanitize the wound if the collar is removed for daily short periods of time, also giving the cat an opportunity for an overall grooming. Scratches and wounds can heal completely using this method. When the cat stops wearing the collar, thinned hair, redness of skin or cracked nipples on the cat are early indicators that the cat has started to over-groom again.

Antidepressants for cats may be suggested by a vet.

Areas affected are those the cat can access most easily, including the abdomen, legs, flank, and chest.

- Baldness, usually beginning with the abdomen

- Obvious over-grooming (although some cats may only engage in the behavior in the absence of owners)

- Redness, rashes, pus, scabs on the bald area or areas traumatized by over-grooming

- A highly irritable cat may even cut its face with the claw of its hind foot if over-zealously scratching the back of its head.

The virus is relatively hardy and immune to many common disinfectants. Exposure to 90% ethanol for at least 1 minute, 2% glutaraldehyde, 30% Savlon, and/or 1% sodium hypochlorite can disinfect the pathogen.

The virus is resistant to drying and heat, but killed by and ultraviolet radiation.

Melanism, meaning a mutation that results in completely dark skin, does not exist in humans. Melanin is the primary determinant of the degree of skin pigmentation and protects the body from harmful ultraviolet radiation. The same ultraviolet radiation is essential for the synthesis of vitamin D in skin, so lighter color of skin - less melanin - is an adaptation for the prehistoric movement of humans away from equatorial regions, as there is less exposure to sunlight at higher latitudes. People from parts of Africa have very dark skin, but this is not melanism.

A number of different species of fungi are involved in dermatophytosis. Dermatophytes of the genera "Trichophyton" and "Microsporum" are the most common causative agents. These fungi attack various parts of the body and lead to the conditions listed below. The Latin names are for the conditions (disease patterns), not the agents that cause them. The disease patterns below identify the type of fungus that causes them only in the cases listed:

- Dermatophytosis

- Tinea pedis (athlete's foot) – fungal infection of the feet

- Tinea unguium – fungal infection of the fingernails and toenails, and the nail bed

- Tinea corporis – fungal infection of the arms, legs, and trunk

- Tinea cruris (jock itch) – fungal infection of the groin area

- Tinea manuum – fungal infection of the hands and palm area

- Tinea capitis – fungal infection of the scalp and hair

- Tinea barbae – fungal infestation of facial hair

- Tinea faciei (face fungus) – fungal infection of the face

- Other superficial mycoses (not classic ringworm, since not caused by dermatophytes)

- Tinea versicolor – caused by "Malassezia furfur"

- Tinea nigra – caused by "Hortaea werneckii"

EN is associated with a wide variety of conditions, including:

- Idiopathic

In about 30–50% of cases, the cause of EN is unknown.

- Infection

- Streptococcal infection which, in children, is by far the most common precipitant,

- Primary infection of Tuberculosis

- "Mycoplasma pneumoniae"

- "Histoplasma capsulatum"

- "Yersinia"

- Epstein-Barr virus

- "Coccidioides immitis" (Valley fever)

- Cat scratch disease

- Autoimmune disorders, including

- Inflammatory bowel disease (IBD)

- Behçet's disease

- Sarcoidosis

- Pregnancy

- Medications, including

- Sulfonamides

- Penicillins

- Oral contraceptives

- Bromides

- Hepatitis B vaccination

- Cancer, including

- Non-Hodgkins lymphoma (NHL)

- Carcinoid tumours

- Pancreatic cancer

EN may also be due to excessive antibody production in lepromatous leprosy leading to deposition of immune complexes.

There is an association with the HLA-B27 histocompatibility antigen, which is present in 65% of patients with erythema nodosum.

A useful mnemonic for causes is SORE SHINS (Streptococci, OCP, Rickettsia, Eponymous (Behçet), Sulfonamides, Hansen's Disease (Leprosy), IBD, NHL, Sarcoidosis.

The Silkie chicken commonly exhibits this trait. In April 2015, an extremely rare black flamingo was spotted on the Mediterranean island of Cyprus.

The diagnosis of flea allergy dermatitis is complicated by the grooming habits of pets. Cats in particular are very efficient at grooming out fleas, often removing any evidence of infestation. Fleas begin biting within 5 minutes of finding a host, and there are no flea treatments that kill fleas before biting occurs.

Aside from the mosquito allergy cat, cats with EGC usually have allergy, ectoparasite infestation or possibly ringworm or other skin infection. Other implicated causes include traumatic damage, autoimmune disease or FeLV infection.

Pathogenic zygomycosis is caused by species in two orders: Mucorales or Entomophthorales, with the former causing far more disease than the latter. These diseases are known as "mucormycosis" and "entomophthoramycosis", respectively.

- Order Mucorales (mucormycosis)

- Family Mucoraceae

- "Absidia" ("Absidia corymbifera")

- "Apophysomyces" ("Apophysomyces elegans" and "Apophysomyces trapeziformis")

- "Mucor" ("Mucor indicus")

- "Rhizomucor" ("Rhizomucor pusillus")

- "Rhizopus" ("Rhizopus oryzae")

- Family Cunninghamellaceae

- "Cunninghamella" ("Cunninghamella bertholletiae")

- Family Thamnidiaceae

- "Cokeromyces" ("Cokeromyces recurvatus")

- Family Saksenaeaceae

- "Saksenaea" ("Saksenaea vasiformis")

- Family Syncephalastraceae

- "Syncephalastrum" ("Syncephalastrum racemosum")

- Order Entomophthorales (entomophthoramycosis)

- Family Basidiobolaceae

- "Basidiobolus" ("Basidiobolus ranarum")

- Family Ancylistaceae

- "Conidiobolus" ("Conidiobolus coronatus/Conidiobolus incongruus")

The aim of treatment is to relieve the allergy-induced itch and to remove the fleas from the pet and its home environment. In some cases, secondary bacterial or yeast infections will also need treatment before the itching subsides. Environmental flea control includes using flea foggers or bombs, vacuuming, and treating pet bedding by washing on a hot cycle (over 60 degrees Celsius) in the washing machine. The current on-pet treatment recommended by veterinary dermatologists is spinosad (Comfortis) monthly and nitenpyram (Capstar or generics) every 48 hours until improvement.

Many pets with FAD may also have other allergies, such as allergies to food, contact allergies, and atopic dermatitis.

Erythema nodosum is the most common form of panniculitis. It is most common in the ages of 20–30, and affects women 3–6 times more than men.

About 15 percent of patients with inflammatory bowel disease develop erythema nodosum.

Pulicosis (also known as "flea bites") is a skin condition caused by several species of fleas, including the cat flea ("Ctenocephalides felis") and dog flea ("Ctenocephalides canis"). This condition can range from mild irritation to severe irritation. In some cases, 48 to 72 hours after being bitten, a more severe rash-like irritation may begin to spread across the body. Symptoms include swelling of the bitten area, erythema, ulcers of the mouth and throat, restlessness, and soreness of the areolae. In extreme cases, within 1 week after being bitten, the condition may spread through the lymph nodes and begin affecting the central nervous system. Permanent nerve damage can occur.

If they receive an excessive number of bites, pets can also develop flea allergy dermatitis, which can potentially be fatal if no actions are taken. However, dogs and cats are not the only ones that are at risk. Humans can suffer from flea bites and, depending on a variety of factors, the bites can cause much pain and discomfort.

Eosinophilic granuloma is a form of Langerhans cell histiocytosis. It is a condition of both human and veterinary pathology. Colloquially, the reaction pattern is sometimes referred to as a rodent ulcer.

Feline eosinophilic granuloma complex is synonymous with "feline eosinophilic skin diseases". This is considered to be a cutaneous reaction pattern that can be the manifestation of a number of underlying infections, allergies or ectoparasite infestations. It can also be idiopathic, that is have no known underlying trigger. The eosinophilic reaction is common in feline inflammatory disease and the eosinophilic granuloma can be a hereditary reaction pattern in some lines of domestic cats.

Pork–cat syndrome is an allergy to pork, usually post adolescence, that is caused by exposure to cats. Although first described in 1994, it was first documented in the U.S. by Scott Commins and Thomas Platts-Mills during their research on alpha-gal allergy.

It is called "pork–cat syndrome" because "almost all people with the condition are cat owners, and many have multiple cats. Some develop an allergic response to cat serum albumin (protein made by a cat’s liver) that cross-reacts with albumin in pork when someone consumes it, and can lead to severe or even fatal allergic reactions when pork is consumed."

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 of dogs and cats can be treated with any of the spot-on preparations available from veterinary surgeons as well as over the counter at many pet stores and online. If the chosen solution does not destroy mite eggs, treatment should be repeated after one month, to catch the next generation of mites that will have hatched by then. Relief, in terms of the cat or dog no longer scratching at his or her ears, will be noticeable within a few hours. However, since mite irritation is partly allergic (see scabies), symptoms may also outlive mites by weeks. Moreover, it may take topical antibiotics and several weeks to clear infected external wounds caused by scratching on the exterior surfaces of cat and dog ears.

Common home remedy treatment options include household ingredients such as isopropyl alcohol, acetic acid (vinegar), boric acid, tea tree oil, coconut oil, and many other plant based extracts, in varying proportions.

Option for treating ear mites in rabbits are the related antiparasitics ivermectin and selamectin. Both of these antiparasitics have also been used with good effect in cats and dogs. A topical preparation of 0.01% ivermectin (Acarexx) can be used directly as an oil in cat ears, and the related new generation drug selamectin (brand name "Revolution") is available as a once-per-month skin treatment for both dogs and cats, which will prevent new mite infestation as well as a number of other parasitic diseases. As with ivermectin, selamectin must be used with caution in collies and herder breeds with the possibility for homozygous MDR1 mutations. A single treatment with a topical formulation containing fipronil, (S)-methoprene, eprinomectin and praziquantel was shown to be efficient for the prevention of "Otodectes cynotis" infestation in cats.

It is caused by either "Bartonella henselae" or "B. quintana".

- "B. henselae" is most often transmitted through a cat scratch or bite, though ticks and fleas may also act as vectors.

- "B. quintana" is usually transmitted by lice.

It can manifest in people with AIDS and rarely appears in those who are immunocompetent.

While curable, BA is potentially fatal if not treated. BA responds dramatically to several antibiotics. Usually, erythromycin will cause the skin lesions to gradually fade away in the next four weeks, resulting in complete recovery. Doxycycline may also be used. However, if the infection does not respond to either of these, the medication is usually changed to tetracycline. If the infection is serious, then a bactericidal medication may be coupled with the antibiotics

If a cat is carrying "Bartonella henselae", then it may not exhibit any symptoms. Cats may be bacteremic for weeks to years, but infection is more common in young cats. Transmission to humans is thought to occur via flea feces inoculated into a cat scratch or bite, and transmission between cats occurs only in the presence of fleas. Therefore, elimination and control of fleas in the cat's environment are key to prevention of infection in both cats and humans.