What Causes Cat Hair Loss?

Numerous possible causes for cat hair loss can make it difficult to come up with an exact reason why a cat is losing hair.

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Cats experience normal shedding, but if abnormal hair loss occurs a veterinarian should be consulted so the skin doesn't get affected. liveslow/iStock/Thinkstock

Some of the more common reasons for cat hair loss, or alopecia as it is more properly termed, include parasites; stress and anxiety; allergies; ringworm and other skin infections; genetics and metabolic causes.

Some hair loss, like shedding their winter or even summer coat, is normal. But if your cat loses a lot of hair, there might be a problem, especially if there are also changes to the skin.

Cats groom themselves often, up to half of the time that they are awake. Excessive grooming above and beyond the norm often results in hair loss, and can even progress to wounds, skin sores and infection. If your cat seems preoccupied with grooming herself more than activities like playing or eating, this may be an indication that something is not right.

Symptoms Of Cat Hair Loss

Inappropriate hair loss can occur in all cats at any stage of life — though there are certain conditions that tend to affect cats at different stages of their lives.

Signs of abnormal hair loss (alopecia) include partial or total hair loss. The skin surrounding the area of hair loss can appear normal, or it can have differing degrees of redness, bumps, scabs and even loss of skin. Alopecia may appear in a symmetrical form, or it can be random on the cat’s skin.

The best way to properly determine the precise cause for the hair loss in your cat is to contact your veterinarian. Along with taking a complete history and performing a comprehensive physical examination, your veterinarian may want to perform diagnostic tests to arrive at the final cause.

Parasitic Causes Of Cat Hair Loss

Parasites, including fleas, mites, lice and ticks, can make your cat itchy and result in scratching and licking, which with time can cause bald spots and even sores.

Even if you believe that there is no way your cat could have fleas, certain patterns of hair loss — especially around the tail base, lower back, thighs, abdomen and flanks — are typically the result of a fleabite hypersensitivity reaction. It never fails to amaze me, and my clients, that many cats with flea infestations are such good groomers that they lick away any evidence of fleas being present.

Your veterinarian can provide several effective treatments for parasites. In some instances, you may need to treat all animals in the house as well as the environment. Here, too, your veterinarian can guide you on what is involved to completely resolve the problem.

Mange mites, like Demodex, burrow under the skin and can cause extreme itching even though they cannot be seen. Mange is typically diagnosed via skin scrapings viewed under a microscope. Notoedres cati is a more common mite that causes alopecia in cats. Hair loss from Notoedres cati is seen on the ears, neck, eyelids and other facial and upper body regions.

Treatment usually involves application of specific approved products under veterinary supervision, as cats can have adverse reactions if products are used inappropriately or combined.

Behavioral Causes Of Cat Hair Loss

Stress and anxiety can affect your cat just as they affect people. Sudden changes in the household — a new baby or pet or even new people in the house — can lead to stress and overgrooming. When stressed, your cat may obsessively lick and scratch, which will result in hair loss. We call this behavioral response to stress “psychogenic alopecia.”

In cats who are affected by psychogenic alopecia, the hair loss tends to be symmetrical and occurs anywhere that the cat can reach with her tongue. The abdomen, flanks and legs are frequent targets. Some suggest that it is more commonly observed in female purebreds — especially those with nervous personalities.

If you find more hairballs than usual, this may be a clue that your cat is excessively grooming. Often a veterinarian will arrive at the diagnosis of psychogenic alopecia after all other underlying conditions have been ruled out.

Treatment can be complicated, as it involves treating the wounds, as well as trying to address the psychological issues. Environmental changes and perhaps even specific medications, like antidepressants, may be necessary.

Allergic Cause Of Cat Hair Loss

Allergies are a very common cause of overgrooming and, therefore, hair loss. Allergies to foods or other substances in the cat’s environment may also result in the loss of hair around the head, neck and possibly other areas. With the hair gone, the exposed skin may look normal or may look irritated or ulcerated as a result of inflammation and possible secondary infection.

Cats can be allergic to foods, insect bites, medicines, dusts, pollens and many of the same other allergens that affect people. To help ease the itch, your cat will lick her fur until there are bald spots. If this overgrooming persists, the spots may increase in size and even become irritated.

The difficult thing for you and your veterinarian to determine is what is causing your cat’s allergy. It can be a single thing or several. Determining the specific allergens involves taking a thorough history of the cat’s diet and environment. Your veterinarian may recommend a trial with a hypoallergenic diet, as well as additional allergy tests or other specific lab tests to get to the bottom of the problem.

Once the allergen(s) has been identified, treatment usually involves eliminating the substance from the cat’s diet or environment. As the allergen works its way out of a cat’s system, itchy rashes begin to fade away. A vet may also prescribe medication to temporarily relieve the worst of the itching.

Once the system returns to normal, most cats will regrow their fur. Allergies are not always easy to treat and, in some cases, as with humans, medications or a special diet may be required long-term.

Cat Hair Loss Caused By Infection

Ringworm infection is actually a fungal infection in the skin that often has circular “ring like,” raised lesions. It is not a worm — nor is it caused by any other type of parasite. It is a fungal skin infection and can result in a scaly, raised ring of missing hair. Your veterinarian can properly diagnose the infection and prescribe appropriate antifungal medications.

A significant bacterial skin infection called pyoderma occurs when the skin is traumatized from scratching and biting. The infection produces localized hair loss, as well as a discharge that crusts over the lesions. Great care must be taken to clean away the discharge to promote healing.

Because pyoderma is often a secondary infection, it is still crucial to determine the primary cause of the irritation. An inflammation of the sebaceous glands, hair follicles or even skin cancer can also lead to hair loss in affected areas.

Genetic Causes Of Cat Hair Loss

Certain purebred cats, such as Himalayans and Bengals, have genes that can cause hair loss. Then there is the Sphynx cat breed, which is bred to be hairless.

A genetic condition called congenital hypotrichosis typically affects Birman, Burmese, Siamese and Devon Rex cats. This disease only causes hair thinning as compared with true alopecia, which leads to actual hair loss.

Metabolic Causes Of Cat Hair Loss

Though not as common, other factors can also disrupt the normal hair growth cycle and lead to sudden hair loss. These include metabolic or endocrine conditions, pregnancy and drug interactions. For example, hair loss can be a symptom of an overactive thyroid or other hormonal imbalances, where the increased levels of thyroid hormone or increased levels of steroids in the body may lead to hair loss.

Because hyperthyroidism is quite common in cats — especially as they age — it is also a leading cause of feline hair loss. Other symptoms of hyperthyroidism include weight loss, decreased or complete cessation in grooming, increased thirst and urination, and an insatiable appetite. Fortunately, in most cases, hyperthyroidism can be effectively treated with medication, surgery or radioactive-iodine therapy.

The opposite of hyperthyroidism is hypothyroidism. Hypothyroidism is a rare condition in cats and is the result of the thyroid gland producing inadequate levels of thyroid hormones to maintain a normal metabolism. The condition causes hair loss, as well of a host of other symptoms that include weakness, weight gain and lethargy.

Feline endocrine alopecia is another rare condition characterized by hair loss on the abdomen, inner legs and genital region. The exact cause of the condition is not completely understood; it is believed to be linked to hormone levels.

Cats with diabetes often have unkempt coats, hair loss and a greater susceptibility to skin infections. Even inflammation in the urinary tract may cause cats to lick the hair off the skin directly above the bladder.

Cushing’s disease, also known as hyperadrenocorticism, is a far less common cause of hair loss. Other symptoms that occur include an increased appetite and thirst, as well as mild to severe lethargy. You may notice that your cat’s skin seems thin, or that petting may now agitate her. The hair loss associated with Cushing’s disease is typically bilaterally symmetrical — the same on both sides. Generally, this hair loss is located on the mid to lower abdomen, but it could occur anywhere on the body.

Other Causes Of Cat Hair Loss

Other immune system problems, like eosinophilic granuloma complex, can result in hair loss. The exact cause of eosinophilic granuloma is not known, but veterinarians speculate that it could be related to an underlying allergy. This condition typically causes irritating lesions that cause reactions around the mouth and hair loss on the back of the thighs.

Even cancer and the immune response associated with it can cause hair loss.

Diagnosing Cat Hair Loss

To properly evaluate your cat and her condition, take your cat to your vet where you can discuss her diet, behavior and environment, as well as have her get a comprehensive physical and perhaps certain lab tests to help pinpoint the cause.

Regarding specific testing, your veterinarian may want to test the blood to check for organ system abnormalities, as well as to determine if there are hormonal or thyroid imbalances causing the alopecia. Various imaging tools, such as X-rays and ultrasound, can be used to look for signs of cancer or abnormalities in the adrenal glands. And, if your veterinarian believes hair loss is due to a specific skin issue, skin scrapes or biopsies or a skin culture may be recommended.

Treatment For Cat Hair Loss

As far as treatment, if the alopecia is due to a skin disorder, thyroid imbalance or other hormonal imbalance, specific medications and topical treatments are available. If hair loss is due to a behavioral issue, modification treatment can be taught to lessen the problem. If it is believed that the hair loss is due to allergies, the solution is avoiding the allergens, which may include dietary changes if the allergy is food-related.

Home Remedies For Cat Hair Loss

To manage hair loss at home, one should observe closely the cat’s behavior and the skin and coat condition to make sure it does not become worse, along with administering the appropriate medication(s). In many instances, a single, surefire method to prevent hair loss in cats may not apply.

Tips For Preventing Cat Hair Loss

It can be difficult to prevent cat hair loss. Prevention depends on the cause and whether you have any control over it. Here’s what you can do at home to help your cat’s skin and fur remain healthy.

  1. Offer high-quality food. The best way to avoid hair loss caused by food allergies or a poor diet is to feed your cat high-quality, healthy food from the onset.
  2. Keep vaccinations current. If you allow your cats to enjoy the outdoors, be sure they are up-to-date with all vaccinations. Not only will this keep them from experiencing any preventable illnesses that could lead to hair loss, vaccinations also stave off much more serious and possibly fatal diseases.
  3. Protect against parasites. For your outdoor cat, use a preventive treatment that protects against all parasites including fleas, mites, heartworms and ticks. Be sure that any preventive you use is specifically formulated for cats.
  4. Seek treatment. It is hoped that if your cat is affected by hair loss, that with the proper treatment, your cat will once again have a full, luxurious coat.

Though I am a veterinarian, the information presented here is not meant to replace your own veterinarian’s professional diagnosis and treatment. If your cat displays any symptoms of hair loss, I recommend that you ask your vet to thoroughly examine your pet to get a proper diagnosis and treatment plan. Your cat’s fur protects her skin, so fur loss can become a serious problem if left untreated.

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Cats · Health and Care

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