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Causes and Treatment for a Cat Losing Hair (Alopecia)

"A cat losing hair is a condition called alopecia, the second most common skin problem after itch. There are many possible reasons for hair loss in a cat, some of them serious and some of them not so serious. The first step is to note if the hair loss is self-induced (skin itch causes cat to groom excessively, pulling out or cutting the hair), or due to a metabolic disease.  The most common cause is skin itch resulting from a reaction to fleas or some type of allergy (hypersensitivities). If an allergic reaction to fleas or some other substance is ruled out, then the veterinarian will move on to other causes that might interfere with hair growth such as metabolic or endocrine based diseases."

cat hair loss - example 1 - miliary dermatitis
Miliary Dermatitis Pattern of Cat Hair Loss on Stomach

Cat Alopecia Symptoms

Alopecia usually causes patches of hair loss. The location of the hair loss will help with the diagnosis with the veterinarian noting if missing hair is in one location or spread over the body in random locations (diffuse) or symmetric (hair loss that is a mirror image on 2 sides of the body). Feline symmetrical hair loss mainly affects the ears, groin, abdomen and truck.  In rare cases it will spread to the legs and head.

Your cat may have other symptoms, as well. Her skin may be red or inflamed where the hair is falling out. She may be scratching or licking those areas resulting in the formation of lesions.. She could have a myriad of other symptoms, depending upon the cause of the hair loss.

Causes

There are four possible causes:

  1. Problems with Follicular Growth: A hereditary or congenital disease can disrupt hair formation.  Certain breeds have genetic diseases that are passed on such as the Canadian hairless cat.
  2. Changes in the Hair Shaft and Follicle: This is caused by some type of infection that leads to inflammation, resulting in the loss of cat hair. Causes include a bacteria (bacterial folliculitis) or fungus (dermophyte), or mange mites that invade the hair follicle (Demodex, commonly referred to as mange).
  3. Interruptions in the Hair Growth Cycle (rare): Certain metabolic or endocrine diseases can cause the hair to weaken and break or fall off. A biopsy can determine the cause of the cat hair loss along with clinical signs and a cat's medical history.
  4. Self-induced cat hair loss (most common): A cat will pull out or cut the hair if suffering from itch.  The mot common causes of self-induced cat hair loss are a parasite such as fleas or allergies (hypersensitivities).  These are described as:
    1. Facial pruritic dermatitis: term used to describe cat hair loss on the face
    2. Miliary dermatitis: a term that describes a skin reaction with many possible causes (it is not a diagnosis). The causes include flea-bites, allergens found in the environment such as pollen (atopy), food allergy, mosquito bites, mites, pemphigus, scabies or a mast cell tumor.
    3. Feline eosinophilic granuloma complex (EGC): result of immune system cells releasing inflammatory chemicals.  Skin reaction is commonly due to the saliva left behind by flea, mosquito or mite bites.  Related conditions are eosinophilic plaque and indolent ulcers.
    4. Psycogenic alopecia (when no other cause can be determine, excessive grooming due to anxiety)
cat hair loss - miliary dermatitis
Cat Hair Loss, Papules and Erosions Related to Miliary Dermatitis

Diagnosis and Treatment

It can be somewhat difficult to diagnose cat alopecia because there are so many possible causes to rule out. Your vet will start with a thorough physical exam. He or she may do a number or special tests, such as blood tests, a urinalysis, examining your cat’s skin under a special light, scraping her skin for some cells to examine under a microscope, and/or a skin biopsy.

Cat Skin Allergies and Alopecia

Cat skin allergies are a common cause of a cat losing hair. Cats can be allergic to things in their environment, such as dust, pollen, and mold (called atopy). This causes red, inflamed spots on the skin, itching, and hair loss. Scratching can make hair loss worse. Allergies are treated with steroids and antihistamines. Your vet can perform allergy tests to determine exactly what that is causing the allergic reaction. If necessary, she can be given allergy shots to desensitize her to that substance.

Food allergies are another possible cause of a cat losing hair. Symptoms look similar to those in cats with environmental allergies. Food allergies are less common than environmental allergies, though. The way to deal with food allergies is to place your cat on a special elimination diet which removes most food types from the diet to see if the reaction disappears. Single foods are gradually added back in. You veterinarian can provide instructions for how to get started.

Alopecia and Cat Fleas

Flea dermatitis can cause cat alopecia. This is an allergy to the saliva from flea bites. It causes small, crusty red bumps, hair loss, and intense itching. Because of the severe itching, your cat may damage her skin and develop a secondary bacterial infection. Your cat must be treated for fleas, and her environment must be treated for fleas as well. If she has a bacterial infection, that will be treated with antibiotics.

picture of cat hair loss
Picture of Cat Hair Loss

The hair loss for flea-bite hypersensitivity is usually in the back half of your cat and areas where your cat cannot easily reach.

Treatment for cat losing hair due to this condition includes the use of flea removal/prevention products such as Frontline Plus for Cats, prescription medications such as glucocorticoids and antihistamines to help with itch. You might also want to supplement the diet with Omega 3, 6, 9 fatty acid Caps which are good for the skin.

Ringworm and Cat Losing Hair

Ringworm is a fungal infection that can cause hair loss. It is not really a worm, but is called ringworm due to its circular appearance. It looks like red circles with white centers. It is treated with both oral and topical medications. The condition can be treated at home wiht a natural product such as Naturasil.

Picture of Cat Ringworm
Picture of Cat Hair Loss - Ringworm

Feline Alopecia and Cat Thyroid Disease

Hair loss can be a symptom of a thyroid disorder called hyperthyroidism. A blood test can determine if your cat’s thyroid is functioning properly. If not, your cat may require surgery to remove part of the thyroid gland.

Cat Skin Fungus (Dermatophytosis)

Cat losing hair due to skin fungus is usually contracted when your cat comes in contact with fungus spores in the dirt or on another animal. The fungus attaches itself to the hair or skin. Signs of infection are seen between 2 to 4 weeks after exposure. Fungus prefers dead cells such as hair and nails and stops spreading when it comes in contact with healthy skin.

The most noticeable symptom of skin fungus is brittle areas or patches of hair which will look the the hair has been closely shaved in the area affected.

Symptoms in kittens include red areas that can be seen on your cat's paw, face and ear. These areas may look like they have a crust that is gray/white in color, covered in wet looking scabs or

The area may develop a thin, grayish white crust or a thick, moist scab. The area may or may not be itchy. Your kitten might spread the fungus all over the body when grooming.

Your veterinarian's diagnosis will be based on a skin test. Treatment options include anti-fungal shampoos and creams.

Cat Psychogenic Dermatitis

Finally, there is psychogenic dermatitis. This is a condition is which cats lick themselves excessively, causing hair loss. It may be caused by anxiety, stress, or boredom. If possible, the source of stress must be relieved, but sometimes behavior modification medication is necessary.

These are the most common causes of cat alopecia. There are other, much rarer causes for a cat losing hair, but your vet will investigate these causes first.

Other Causes of Cat Losing Hair or Cat Alopecia:

A cat can also loose its' hair due when taking certain drugs (known as antimitotic drugs) or when the body is under stress from a severe disease. Other stresses on your cat's body such as fever, shock or surgery can also cause the hair to stop growing within 1 to 3 months of the problem. If you can identify any of these as the cause of the hair loss, then the problem should eventually heal itself, particularly if your cat is no longer taking a drug that caused the problem.

Ask our Vet a Question about Cat Hair Loss

Have a question about cat hair loss? Our veterinarian will answer it for free. To help provide the best answer possible, please include your cat's medical history such as age, breed, medications, skin condition, location your cat is losing hair and any changes in behavior. Please include a picture if you can.

We will do our best to answer questions quickly (it depends on how many we receive each day). If you need an immediate response we suggest using this online cat veterinary answer service that is available 24 hours a day.

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References for a Cat Losing Hair:

Causes of Hair Loss
Holly Nash, DVM

The Center for Food Security and Public Health
Iowa State University
College of Veterinary Medicine

Cats that Lick Too Much

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