Hair Loss (Alopecia) in Cats

Key Takeaways

Feline alopecia or hair loss is the partial or complete absence of hair in areas of the body where hair is expected to be. 

• Hair loss is common in cats and can be present at birth or develop later in life

• Alopecia is not to be confused with shedding, which is a normal and healthy characteristic in cats and does not cause bald spots

• Hair loss can be due to injury to the skin, damage to the hair follicles, or hair growth cycle abnormalities

• Alopecia can be caused by a wide array of underlying conditions, some of which can be life-threatening

• Diagnosis includes an in-depth dermatological examination, blood tests, urinalysis, and skin biopsy

• Treatment options include flea and mite medications, behavioral therapy, and antibiotics depending on the underlying condition

• Prognosis varies depending on the underlying cause

A Closer Look: What is Hair Loss in Cats?

In general, alopecia is caused by one of three changes: injury, hair follicle damage, or hair growth cycle abnormalities.

Feline alopecia can be categorized in many different ways:

Acquired or congenital alopecia: Congenital alopecia presents at birth and is caused by lack of hair follicle development. Hair loss may be apparent shortly after birth or can occur when the animal is older. Acquired alopecia occurs when the animal is born with healthy hair follicles but develops the inability to produce normal hair due to an underlying condition. 

Symmetrical or asymmetrical alopecia: Symmetrical alopecia occurs when hair loss is present on both sides of the animal’s body. Symmetrical alopecia can be both congenital and acquired. Asymmetrical alopecia occurs when hair loss is present only on one side of the body. 

Localized or generalized alopecia: Alopecia can present as localized to one area of the animal's body, or generalized affecting the whole body. Non-inflammatory or inflammatory alopecia

Itchy or non-itchy: many causes of alopecia, particularly non-infectious causes, do not cause itchiness.

Possible Causes

Alopecia can be caused by a number of underlying medical conditions, including: 

Allergic conditions, such as flea allergy dermatitis, inhalant allergies (atopy) and food allergies

Mites and other parasites, particularly Demodex mites 

Fungal skin infection (dermatophytosis)

Viral infections such as herpesvirus or papillomavirus

Bacterial infections, such as bacterial folliculitis

Traumatic injuries, such as burns, frostbite or scars 

Endocrine disorders, such as hyperthyroidism, hyperadrenocorticism, and diabetes mellitus

Autoimmune conditions such as alopecia areata or pemphigus foliaceus

Psychogenic alopecia: a behavioral issue that occurs when the animal compulsively and excessively grooms

Risk Factors

Alopecia is a common symptom in cats. A wide range of underlying conditions can cause hair loss, some of which can be life-threatening. Prognosis depends on the underlying cause. Hair loss may be permanent, especially when it is caused by damage to the hair follicle. Veterinary attention is crucial in detecting the underlying cause early, which increases the probability of a good prognosis.

Testing and Diagnosis

Diagnostic tools ton investigate hair loss include: 

• Physical examination • Blood tests • Urinalysis

• Full dermatological database: including skins scrape, skin cytology, skin and fungal cultures, and Wood’s lamp evaluation

• Skin biopsy: usually only undertaken if the dermatological examinations do not determine the underlying cause

• Therapeutic trials of antiparasitic medications, allergy medications, or pain medications to rule out conditions

Once the underlying cause is determined, treatment depends on the underlying cause and may include: 

• Flea and mite medication • Allergy medication • Antibiotics  • Pain medication • Topical medications

• Behavioral therapy and behavioral medication in the case of psychogenic alopecia

Note: many topical formulations of medications and shampoos are toxic to cats. Always consult a veterinarian before using topical treatments on cats.

Similar symptoms

Normal shedding can be mistaken for alopecia. Shedding is a normal and healthy characteristic of cats. Any amount of shedding is considered normal. Shedding differs from alopecia as shedding does not cause bald spots.

Associated Symptoms

Cats suffering from alopecia may present a number of additional symptoms, including but not limited to:

• Rashes • Itchiness • Red skin • Open sores  • Scabs • Excessive grooming