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.

Psychogenic alopecia, also called "over-grooming" or "psychological baldness," is a compulsive behavior that affects domestic cats. Generally, psychogenic alopecia does not lead to serious health consequences or a decreased lifespan.

Lick granuloma is a form of self-trauma and skin disorder in which most commonly dogs, but also cats, continuously lick a small area of their body until it becomes raw and inflamed. The most common areas affected are the lower (distal) portions of their legs, such as the carpus (wrist), or sometimes another part of their body such as the base of their tail.

The lesion can initially be red, shiny, swollen, hairless, irritated, and bleeding, similar to a hot spot (wet eczema). Eventually a raised hard plaque forms.

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.

A lick granuloma, also known as acral lick dermatitis, is a skin disorder found most commonly in dogs, but also in cats. In dogs, it results typically from the dog's urge to lick the lower portion of one of his or her legs.

The lesion can initially be red, swollen, irritated, and bleeding, similar to a hot spot (wet eczema). The animal's incessant licking of the lesion eventually results in a thickened, firm, oval plaque, which is the granuloma.

A major cause of lick granuloma appears to be psychological, related to stress, anxiety, separation anxiety, boredom, or compulsiveness. Lick granulomas are especially seen in active dogs left alone for long periods of time. One theory is that excessive licking causes endorphin release, which reduces pain and makes the animal feel euphoric temporarily; that effect then causes an addiction to licking.

Other triggers include itchy skin, painful conditions caused by trauma to the skin, arthritis, neuralgia, and peripheral neuropathy. A bacterial or fungal infection of the skin can also trigger itching, as can skin mites, allergies, a reaction to an environmental irritant or toxin, hyperthyroidism, and certain types of cancer.

Treatment of the primary cause, if known, is essential. In psychogenic cases, psychological factors should be identified and addressed, such as being left alone all day, being confined, and changes in the household.

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.

Some diseases are inherent abnormalities of skin structure or function. These include skin fragility syndrome (Ehlers-Danlos), hereditary hypotrichosis and congenital or hereditary alopecia.

Traction alopecia is a form of alopecia, or gradual hair loss, caused primarily by pulling force being applied to the hair. This commonly results from the sufferer frequently wearing their hair in a particularly tight ponytail, pigtails, or braids. It is also seen occasionally in long-haired people who use barrettes to keep hair out of their faces. Traction alopecia is recession of the hairline due to chronic traction, or hair pulling, and is characterized by a fringe along the marginal hairline on physical exam. Even though this "fringe sign" is considered a useful clinical marker of this condition, cases of frontal fibrosing alopecia presenting with an unusual retention of the hairline (pseudo-fringe sign) have been described.

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

Symptoms of hair loss include hair loss in patches usually in circular patterns, dandruff, skin lesions, and scarring. Alopecia areata (mild – medium level) usually shows in unusual hair loss areas e.g. eyebrows, backside of the head or above the ears where usually the male pattern baldness does not affect. In male-pattern hair loss, loss and thinning begin at the temples and the crown and either thins out or falls out. Female-pattern hair loss occurs at the frontal and parietal.

People have between 100,000 and 150,000 hairs on their head. The number of strands normally lost in a day varies, but on average is 100. In order to maintain a normal volume, hair must be replaced at the same rate at which it is lost. The first signs of hair thinning that people will often notice are more hairs than usual left in the hairbrush after brushing or in the basin after shampooing. Styling can also reveal areas of thinning, such as a wider parting or a thinning crown.

Pityriasis amiantacea (also known as "Tinea amiantacea") is an eczematous condition of the scalp in which thick tenaciously adherent scale infiltrates and surrounds the base of a group of scalp hairs. It does not result in scarring or alopecia.

Pityriasis amiantacea was first described by Alibert in 1832. Pityriasis amiantacea affects the scalp as shiny asbestos-like (amiantaceus) thick scales attached in layers to the hair shaft. The scales surround and bind down tufts of hair. The condition can be localised or covering over the entire scalp. Temporary alopecia and scarring alopecia may occur due to repeated removal of hairs attached to the scale. It is a rare disease with a female predilection.

Pityriasis amiantacea can easily be misdiagnosed due its close resemblance to other scalp diseases such as psoriasis, seborrhoeic dermatitis or lichen planus. However in pityriasis amiantacea the scales are attached to both the hair shaft and the scalp. Pityriasis amiantacea may be present with other inflammatory conditions such as atopic dermatitis or seborrhoeic dermatitis and sebaceous scales and alopecia can occur. According to the dermatology text Bolognia this condition is most often seen in psoriasis, but may also be seen in secondarily infected atopic dermatitis, seborrheic dermatitis, and tinea capitis.

Typical first symptoms of alopecia areata are small bald patches. The underlying skin is unscarred and looks superficially normal. Although these patches can take many shapes, they are usually round or oval. Alopecia areata most often affects the scalp and beard, but may occur on any part of the body with hair. Different areas of the skin may exhibit hair loss and regrowth at the same time. The disease may also go into remission for a time, or may be permanent. It is common in children.

The area of hair loss may tingle or be painful. The hair tends to fall out over a short period of time, with the loss commonly occurring more on one side of the scalp than the other.

Exclamation point hairs, narrower along the length of the strand closer to the base, producing a characteristic "exclamation point" appearance, are often present.

When healthy hair is pulled out, at most a few should come out, and ripped hair should not be distributed evenly across the tugged portion of the scalp. In cases of alopecia areata, hair will tend to pull out more easily along the edge of the patch where the follicles are already being attacked by the body's immune system than away from the patch where they are still healthy.

Nails may have pitting or trachyonychia.

A substantially blemished face, back and limbs could point to cystic acne. The most severe form of the condition, cystic acne arises from the same hormonal imbalances that cause hair loss, and is associated with dihydrotestosterone production. Seborrheic dermatitis, a condition in which an excessive amount of sebum is produced and builds up on the scalp (looking like an adult cradle cap) is also a symptom of hormonal imbalances, as is an excessively oily or dry scalp. Both can cause hair thinning.

Telogen effluvium is a scalp disorder characterized by the thinning or shedding of hair resulting from the early entry of hair in the telogen phase (the resting phase of the hair follicle). Emotional or physiological stress may result in an alteration of the normal hair cycle and cause the disorder, with potential causes including eating disorders, fever, childbirth, chronic illness, major surgery, anemia, severe emotional disorders, crash diets, hypothyroidism, and drugs.

Diagnostic tests, which may be performed to verify the diagnosis, include a trichogram, trichoscopy and biopsy. Effluvium can present with similar appearance to alopecia totalis, with further distinction by clinical course, microscopic examination of plucked follicles, or biopsy of the scalp. Histology would show telogen hair follicles in the dermis with minimal inflammation in effluvium, and dense peribulbar lymphocytic infiltrate in alopecia totalis.

Vitamin D levels may also play a role in normal hair cycle.

It is important to continue to watch for symptoms and signs of active disease during and after treatment to ensure that the disease is responding adequately and has not re-activated after therapy has been discontinued. Response to therapy may be indicated by the resolution of scalp symptoms such as itching, pain, tenderness, or burning, by improvement in the signs of scalp inflammation such as decreased redness, scaling or pustules, and by halting or slowing the progression of hair loss. A dermatologist can follow your cicatricial alopecia using these guidelines, and with the pull test. Photographs of the scalp may be useful in monitoring the course of the disease and response to treatment.

The bacteria staphylococci are present in the majority of cases. Treatment with systemic antibiotics and coal tar shampoo can completely clear the condition when Staphylococcus aureus bacteria are found. Fungal infections such as tinea capitis are known to mimic the symptoms of the condition and can be cleared with antifungal treatment.

Scarring hair loss, also known as cicatricial alopecia, is the loss of hair which is accompanied with scarring. This is in contrast to non scarring hair loss.

It can be caused by a diverse group of rare disorders that destroy the hair follicle, replace it with scar tissue, and cause permanent hair loss. A variety of distributions are possible. In some cases, hair loss is gradual, without symptoms, and is unnoticed for long periods. In other cases, hair loss is associated with severe itching, burning and pain and is rapidly progressive. The inflammation that destroys the follicle is below the skin surface and there is usually no "scar" seen on the scalp. Affected areas of the scalp may show little signs of inflammation, or have redness, scaling, increased or decreased pigmentation, pustules, or draining sinuses. Scarring hair loss occurs in otherwise healthy men and women of all ages and is seen worldwide.

It is commonly seen with certain hair styles or braiding patterns that pull the hairline forcefully towards the vertex of the scalp, and has been reported more often in African American women (as some wear their hair tightly pulled back), in whom it can cause scarring. It has also been seen in female ballerinas, and in cultural traditions where the hair is voluntarily not cut in religious obeisance, the latter caused by progressively increasing weight of the hair itself. Traction alopecia is mechanical in cause, rather than androgenic, and treatment is typically not pharmaceutical. Management includes cessation of the chronic traction, cosmeses, with surgical restoration reserved for more severe cases.

Traction alopecia is a substantial risk in hair weaves, which can be worn either to conceal hair loss, or purely for cosmetic purposes. The former involves creating a braid around the head below the existing hairline, to which an extended-wear hairpiece, or wig, is attached. Since the hair of the braid is still growing, it requires frequent maintenance, which involves the hairpiece being removed, the natural hair braided again, and the piece snugly reattached. The tight braiding and snug hairpiece cause tension on the hair that is already at risk for falling out. Traction Alopecia is one of the most common causes of hair loss in African American women.

Sikh men are also susceptible to traction alopecia if the hair under the turban is tied too tightly for many years.

Other causes include:

- Hairstyle. Although the aforementioned style is one of the culprits, hairstyles such as dreadlocks and single (extension) braids can also have the same effect. Men and women who have suffered from traction alopecia have found that the hair loss occurs most at the hair line—primarily around the temples and the sides of their heads.

- Headgear. Compressive safety helmets worn tightly and closely to the scalp are a cause of traction alopecia. The lining of tightly fitted safety helmets like those worn for activities such as motorcycling, cycling, skiing and snowboarding are responsible for the constant rubbing and tugging of localised areas of the hair and scalp. Frequent wearers or those who use such helmets for prolonged periods seem more likely to suffer traction alopecia.

- Chemicals. A condition known as CCCA (central cicatricial centrifugal alopecia), seen almost exclusively in African American women, can cause extensive hair loss. It is caused by a combination of too much stress (traction) on the hair and the use of harsh relaxers and dyes.

CCCA usually begins at the central (sagittal) midline of the scalp. It is symmetric and exhibits scarring as the name suggests. It involves solely the top of the scalp or may progress to Hamilton–Norwood scale Type VI or VII. Early symptoms may include pruritus, dysesthesias and tenderness. On examination the skin is thin with few follicular ostia and later in the disease the scalp may appear shiny.

Trachyonychia, sometimes called sandpapered nails, is a condition characterized by rough accentuated linear ridges (longitudinal striations) on the nails of the fingers and toes. When the condition occurs on all the twenty nails of the fingers and toes, it is known as twenty-nail dystrophy, most evident in childhood, favoring males.

Trachyonychia causes the nails to become opalescent, thin, dull, fragile, and finely longitudinally ridged, and, as a result, distally notched. It can be a manifestation of lichen planus, psoriasis, alopecia areata, immunoglobulin A deficiency, atopic dermatitis, and ichthyosis vulgaris.

"The longitudinal striations can occur as a normal part of the aging process", and not until the nails start to thin and get a sandpaper look is the condition called trachonychia. The nails are opalescent and frequently are brittle and split at the free margin. There has been evidence of the condition as a cutaneous manifestation of lichen planus. It has also been associated with other diseases such as eczema, psoriasis, alopecia areata, and atopic dermatitis. Trachonychia is often seen in vitiligo patients – suggesting that they are more susceptible to this condition.

Pseudopelade of Brocq (also known as "Alopecia cicatrisata") is a flesh- to pink-colored, irregularly shaped alopecia that may begin in a moth-eaten pattern with eventual coalescence into larger patches of alopecia.

Central centrifugal cicatricial alopecia (CCCA), also referred to as hot comb alopecia and follicular degeneration syndrome, is a type of alopecia first noticed in African Americans in the 1950s and reported by LoPresti et al. in 1968 as a result of application of petrolatum followed by a stove-heated iron comb. The original theory was that the hot petrolatum would travel down to the hair root, burn the follicle, and after repetitive injury scarring would result. Later CCCA was realized to affect men and women without a history significant for use of such styling techniques. Consequently, the terms "follicular degeneration syndrome" per Sperling and Sau in 1992 and then CCCA per Olsent et al. in 2003 were evolved. Plausible contributing factors may include other African-American styling techniques such as relaxers, tight braids, heavy extensions, certain oils, gels or pomades.

Important diagnoses to consider include female pattern hair loss (FPHL), chronic telogen effluvium (CTE), and alopecia areata (AA). FPHL is a non-scarring progressive miniaturization of the hair follicle with one of three different characteristic patterns. CTE is an idiopathic disease causing increased hair shedding and bi-temporal recession, usually in middle aged women. AA is an autoimmune attack of hair follicles that usually causes hair to fall out in small round patches.

In most cases which begin with a small number of patches of hair loss, hair grows back after a few months to a year. In cases with a greater number of patches, hair can either grow back or progress to alopecia areata totalis or, in rare cases, alopecia areata universalis.

There is no loss of body function, and effects of alopecial areata are mainly psychological (loss of self-image due to hair loss), although these can be severe. Loss of hair also means the scalp burns more easily in the sun. Patients may also have aberrant nail formation because keratin forms both hair and nails.

Hair may grow back and then fall out again later. This may not indicate a recurrence of the condition, but rather a natural cycle of growth-and-shedding from a relatively synchronised start; such a pattern will fade over time. Episodes of alopecia areata before puberty predispose to chronic recurrence of the condition.

Alopecia can be the cause of psychological stress. Because hair loss can lead to significant changes in appearance, individuals with it may experience social phobia, anxiety, and depression.

The management of hair loss, also known as alopecia or baldness, may include medications and surgery.