cat pulling clumps of fur out with its teeth
Cat Health and Wellness

Why Do Cats Pull Their Fur Out in Chunks?

Cats normally have two shedding seasons in a single year. One happens after winter to shed their winter coat for the warmer weather. The second comes before fall to prepare for the growth of their cold-weather coat. However, this is not the same as abnormal shedding and fur loss.

Cats lose or pull their fur out in chunks due to medical illnesses or disease, allergies (environmental, insect, or food-related), skin parasites, sudden changes to their environment, or because they are a certain breed of cat. The most common illnesses that cause this problem are hyperthyroidism, alopecia, cancer, heart disease, or diabetes. Skin parasites that are the main culprits include fleas, lice, ticks, and skin mites. Other factors, such as intestinal parasites, dermatitis, nutritional deficiencies, or injuries from conflict, can cause your cat to lose clumps of fur.

If your elderly cat is pulling fur out, it is most likely because of arthritis pain, hyperthyroidism, and/or nutritional deficiencies. To help your cat, you must narrow down the exact reason. A few of the symptoms may coincide, or they may be independent. No matter the case, take note of all your cat’s abnormal behavior and consult a vet.

Why Does My Cat’s Fur Clump Up?

When a cat is shedding, it’s natural for its fur to clump up. This is because cats shed their undercoat, so the fur gets caught in the top coat. It stays there as more thin strands add to the bulk and eventually form a clump. The clump gets loose over time and activity and is deposited in your house as a large furball.

Of course, cats may also lose clumps of fur outside of the shedding season. Felines lose hair at all times. If the cat is especially oily or dirty, the individual strands will get caught up in the top coat. Like with shedding, the fur will gather until it’s shaken loose as a clump. You can limit this clumping when you brush the fur and remove the extra.

However, if your cat is always losing hair in clumps, this is a reason to be concerned. Cats are ritual groomers, so it’s unnatural for them to ignore clumps in their fur. They should have a strong desire to clean themselves up. If your cat seems to avoid grooming, this could be a sign of stress or illness.

Why is My Cat Losing Clumps of Fur?

Cats should not be shedding large clumps of fur on a regular basis. Outside of shedding season, this means your cat is potentially dealing with:

  • Allergies
  • Skin parasites
  • Intestinal parasites
  • Illness or disease
  • Dermatitis
  • Stress
  • Nutrition deficits
  • Rough activity

Of course, these causes are not mutually exclusive. They can easily overlap with one another.


Dermatitis describes any type of inflammation of the skin. Your cat can develop dermatitis for several reasons, such as:

  • Skin and/or intestinal parasites
  • Stress
  • Nutrition deficits
  • Allergens
  • Injury

Despite these variable causes, dermatitis symptoms are often the same. Symptoms include:

  • Itchiness
  • Scaling of the skin
  • Redness
  • Inflammation
  • If left untreated, scabbing and infection

Nutrition Deficiencies

Even a cat that’s loved and properly cared for may run into nutritional deficiencies. That’s because this illness includes:

  • A lack of one or more nutrients
  • An excess of nutrients
  • A combination of both

A balance is necessary for your cat to grow and maintain healthy fur. In particular, fatty acids and omega-3s are beneficial for maintaining your cat’s skin and fur health. With enough, it can even bounce back from deficiencies better than before.

When this doesn’t happen, the cat’s fur begins to fall out. If the cat’s skin is also struggling, this can lead to hair clumping. The most common deficiencies include:  

  • Low fat content
  • Protein or fat content of poor quality
  • Low digestibility
  • High levels of nutrients, which inhibit the way other nutrients are absorbed
  • A deficiency of essential fatty acid (EFA) deficiency

A lack of EFA, in particular, can result in:

  • Scaly and dry skin
  • Matted fur
  • Less elastic skin
  • Higher susceptibility to infection

Furthermore, copper deficiency can cause:

  • Dull, dry fur coats
  • Patchy hair loss
  • Loss of hair pigment

Why Does My Cat Keep Pulling Hair Out?

It’s scary to find your cat frantically pulling out its own hair. This is not natural behavior. While cats do groom themselves and remove shed hair, it’s not excessive. A cat that’s removing large clumps on a regular basis is experiencing a serious health issue.

You may even find the cat biting, yowling, and scratching at itself. If you find your cat pulling out fur and losing weight, you’ll need the intervention of a vet. It could mean that your cat is dealing with:

A Medical Illness

Several medical illnesses result in your cat pulling out fur and losing weight. These include:


Hyperthyroidism is a disease that is characterized by a hyperactive thyroid gland. This occurs because of the excessive production of thyroid hormones. As such, the thyroid gland is stimulated far more than necessary.

Hyperthyroidism can increase your cat’s metabolism, causing it to lose weight faster than it can possibly gain by eating. When it gets malnourished, it will also start losing fur. Certain cat species are genetically predisposed to develop hyperthyroidism.

cat shedding fur in clumps

Cancer And Heart Disease

Both cancer and heart disease can result in a cat losing excessive amounts of hair. It will also begin losing weight, either from the diseases themselves or from a lack of appetite.


Diabetes develops from a lack of insulin production. Insulin is a hormone that is primarily responsible for regulating the sugar levels in the blood. With a lack of insulin, your cat may begin losing weight, and its fur coat may decrease in quality. This can contribute to your cat pulling out its own fur.

Alopecia (Hair Loss)

One common theme across all of these diseases is that they cause alopecia, or hair loss. It is a common symptom of illness in cats. Sadly, that also makes it difficult to narrow down the exact cause. It’s best to rely on veterinarians to test for medical issues. They can help you determine what is ailing your cat.


Cats may develop allergic reactions. Their fur is capable of picking up spores, dirt, and pollen that can impact their health. According to The University of Rio Grande Do Sul, Persian cats often host a dermatophyte infection, or fungi. How badly a cat will be affected (if at all) depends on the feline’s health, environment, and genes.

The most common response to an allergen is itchy skin. Known as pruritus, this further exacerbates hair loss. Your cat may even lose its appetite from all the stress and thus begin shedding weight too.

Allergic reactions can cause miliary dermatitis in cats. This is a skin condition characterized by flaky, itchy rashes. It can be aggravated when your cat scratches, licks, or rubs the spot for relief. If your cat gets obsessive, it can result in:

  • Large bare patches where hair refuses to grow
  • The formation of scabs
  • In the worst-case scenario, full-blown skin infections 

Miliary dermatitis can also cause thinning of the fur, making your cat shed fur at a rapid pace. The most commonly affected areas are the:

  • Lower spine
  • Base of the tail
  • Face
  • Ears
  • Neck
  • Flank
  • Belly

But where did your cat pick up these allergies? There can be many causes, such as:

Environmental Allergens

Depending on where your cat spends the majority it of its time, it may be exposed to:

  • Pollen
  • Grass
  • Fungi
  • Mold
  • Dust
  • Cigarette smoke
  • Perfume or cologne, other fragrances
  • Cleaning products

According to Mycoses, stray cats are very prone to picking up multiple kinds of fungi. This lives on and in their fur, thriving on the warmth, any dampness, and dead skin cells. If your cat was previously a stray, there’s a higher chance that its fur loss is caused by this.

Insect Allergens

Cats are good hunters and often target insects to eat and play with. However, the bugs may fight back, directly or indirectly. If your cat happens to develop an allergy from one of these insects, it can affect the cat’s fur:

  • Fleas
  • Spiders
  • Ticks
  • Ants
  • Bees
  • Wasps

Food Allergies

Of course, your cat’s meals are also at risk. These food types may trigger allergies in certain cats, no matter how natural they seem:

  • Beef
  • Fish
  • Chicken
  • Dairy

Skin Parasites

There are a multitude of parasites that can infect a cat. However, skin parasites are more commonly associated with hair loss. According to Veterinary Parasitology, the parasites can even live on inside the fur once it’s shed. This can spread the invaders around your home, infecting you and other pets.

The good news is, an infestation of ectoparasites (or skin parasites) on your cat is typically unique to its species. In other words, the invaders may be biologically unable to infect people as their host.

That’s not always true, however, so you should be cautious. If you are unsure, take the necessary precautions and contact your veterinarian. Alongside fur clumping, your cat may experience a loss of appetite. This is caused by the stress its body experiences when hosting the parasites.

If you suspect that your cat is losing fur due to skin parasites, these are the top culprits:

  • Fleas
  • Lice
  • Skin mites
  • Ticks


Flea bites may encourage your cat to incessantly itch. This can lead to excessive fur loss, either by scratching or by manually pulling out hair. Because your cat’s claws are sharp, constant itching in the same area will lead to open wounds and infections. Over time, these can develop into scabs.

The fur loss and scabs will be localized where the fleas decide to live on your cat’s body. The most common areas include the:

  • Lower back
  • Thighs
  • Belly
  • Head
  • Around the neck
  • Even the tip of the tail

You can usually tell your cat has fleas if it itches its body obsessively. If you find your cat pulling fur out on its belly, this is an obvious sign of fleas. These bugs are more common if you live in a warm and muggy climate. The temperature conditions allow fleas to thrive.

Do not be fooled into thinking that your cat is safe just because it’s wintertime. Fleas can still survive in the cold, especially if they have a warm host to live on. Fleas are known as the number one cause of allergic reactions and skin problems in domestic cats.

Intestinal parasites, namely tapeworms, can also accompany flea infestations. This happens when your cat ingests fleas during grooming. They are infamous for harboring many other diseases and microparasites.


Lice may cause itchy skin, scratching, and hair loss in clumps. Lice infections are more commonly seen in elderly cats. Therefore, if you find your older feline pulling out hair, you should check it over for signs immediately.

Do not worry about lice transferring to you or any other people within the home. Lice that infect cats typically do not pick humans as their host.

Skin Mites

Skin mites will lead to cats pulling out their own fur or developing scabs. However, compared to fleas and lice, they are far less common.

Ear mites are actually seen more often in cats than basic skin mites. These skin parasites are more difficult to spot visibly on your cat’s fur or skin. That’s because they are likely to be ingested by your cat during grooming.


Your cat is more likely to be exposed, and vulnerable, to ticks if they are outdoor cats. That’s because most tick species that use cats as a primary host can be found on the:

  • Tips of grass
  • Leaves of shrubs

Much like the other skin parasites, a tick bite can lead to skin rashes. This results in excessive scratching and fur loss. If your feline cannot ease the itchiness, it will opt to pull fur out in chunks as a temporary remedy. Like fleas, ticks are also carriers of various other diseases that can be harmful to both humans and cats alike.

There are a wide variety of tick species throughout the world, but only a few utilize cats as their primary host. These vary depending on the region. Here are the most prominent ones to attack cats in North America:

  • American dog tick
  • Lone star tick
  • Deer/blacklegged tick
  • Brown dog tick
  • Longhorned tick

Ticks are rather dangerous parasites, and you should be especially cautious of the longhorned tick. This species was recently introduced into the United States. As such, the Center for Disease Control and Prevention is still researching the possible bacteria and diseases it can and cannot spread. If you live in states where the longhorned tick is found, make sure your cat is not let outside.

Sudden Changes To The Cat’s Environment

Cats much prefer a day-to-day routine and predictability in their everyday life. As such, sudden changes to their environment can be extremely distressing. They may trigger stress responses in your cat, leading to fur-pulling and weight loss.

Changes to your cat’s environment go hand in hand with medical causes, allergies, and skin parasite infestations. However, there does not have to be a medical reason for your cat to be stressed. Triggers include:

  • Conflict amongst other cats (domestic and feral) or people
  • Changes to (or replacements of) well-liked bedding, housing, or toys
  • Fluctuations in temperature
  • Loud noises
  • Bright lights
  • Unfamiliar people or other animals
  • Limiting space availability
  • Changing location (moving to a new place, living with new owners, etc.)
  • Extreme boredom
  • Loneliness

Stress can induce what is known as psychogenic alopecia, which is hair loss caused by extreme stress. If your cat is tearing its fur out, but there is no medical explanation, it’s likely the feline is exhibiting psychogenic alopecia. Compared to normal alopecia, this condition is the forced tearing of any fur from the body. It’s not a result of weak hair follicles making it easier to do so.

Of course, not all environmental changes which cause fur loss are inherently negative. Changes that seem innocent on the surface may lead to hair-pulling. These include:

  • Introducing new pets, babies, or children
  • Adding new toys, household items, scents
  • Having guests over in the house on a regular basis

The above items are not intentionally stressful, but depending on your cat, they may be. Make sure that nervous or anxious cats have a space to retreat to. Likewise, any new people, toys, or environments should be introduced slowly. Never force your cat to accept something (or someone) at the drop of a hat. While most cats respond with aggression, yours may respond with more self-destructive behavior.

Certain Cat Breeds

Certain cat breeds are genetically predisposed to fur loss and, thus, pulling their own hair out. They may have just inherited weaker hair follicles, making it easier to remove the fur themselves. These cat breeds are typically pure-bred, oriental breeds, such as:

  • Burmese
  • Siamese
  • Bengal

That’s because these purebred breeds have 2 copies of a non-dominant gene that results in a susceptibility to fur loss. This is found particularly in the Burmese and Siamese breeds.

It is also autosomal, or hereditary. As such, it’s passed throughout the generations and persists even if your cat’s parents or grandparents didn’t exhibit it.

Other cat breeds typically have one or no copies of the non-dominant gene that controls a vulnerability to hair loss. As such, we do not see genetic causes of fur loss in other breeds.

cat pulling out fur and losing weight

Why is My Elderly Cat Pulling Fur Out?

Older cats pull out their hair for the same reasons that we discussed above. However, there are extra causes that affect elderly cats more than kittens or younger cats.


As your cat ages, its joints can experience wear and tear. This leaves it vulnerable to arthritis, which is characterized by inflammation of the joints.

Of course, grooming is soothing to cats. Elderly felines may begin licking and pulling fur out from areas where they feel arthritis pain. If your elderly cat is pulling fur out around its legs and thighs, arthritis may be the cause.


Elderly cats are more likely to develop hyperthyroidism than younger cats. Cats 13 years or older are susceptible to this medical disease.

Nutrient Deficiencies

Older cats are also more sensitive to diet changes or deficiencies. The older they get, the more scrutiny you, the owner, must place on their diet. Their bodies are becoming less efficient at maintaining their health, after all.

Poor diet, especially in elderly cats, can result in dull fur and weak hair follicles. This can make fur pulling much easier.

Is It Dangerous For Cats To Lose Hair In Clumps?

If you see any signs of illness (or even stress) in your cat, do not hesitate to call your veterinarian and set an appointment. Hair loss can be a serious condition in cats. They may:

  • Be unable to regulate their body temperature
  • Be more exposed and vulnerable to the sun
  • Damage their skin while pulling out hair
  • Create wounds that lead to infection
  • Damage hair follicles and stop the hair from growing back

By catching the fur-pulling problem sufficiently early, you can implement a solution. This will mean that your cat’s fur can grow back thick, strong, and healthy.