Since cats spend so much of their time grooming, their coats usually look shiny and neat.
However, there are some situations that can make your cat’s fur look dull. For instance, some kind of skin condition can cause an unusual look of your cat’s fur.
Also, if you exaggerate with bathing your cat, this can have the opposite effect and make your cat’s fur actually look worse.
You may also notice that your cat’s fur appears lumpy.
Why does this occur? Why has my cat’s fur gone lumpy?
There are nine potential explanations for this occurrence in felines. Most of them are health-related, so you should be well acquainted with each one of them, and know what to do to help your pet.
1. Mats And Tangles In A Cat’s Fur
In many cases, a cat’s fur will look lumpy due to mats and tangles.
PetVet Care explains how this mostly occurs in long-haired cats. When they shed a lot of fur, it can easily become tangled, especially in the chest and leg areas, resulting in a lumpy appearance.
Together with the fur, mats consist of dirt and dead skin cells.
Even though a cat does great work cat grooming itself, its fur still can get tangled. Cats with long hair could simply have too much fur to take proper care of it all.
Neglecting matted fur can cause significant discomfort for a cat. A coat like this can even become itchy and lead to inflammation.
Therefore, if you notice this, you should help your pet. The best way to do this is by using a mat breaker to brush the tangles out.
In some cases, a cat’s fur can get severely matted, and this is when it’s necessary to reach out to a vet or a professional groomer. You shouldn’t shave your cat’s fur on your own, no matter how big the matting problem is.
The best way to prevent mats and tangles in your cat’s coat is by regularly brushing it.
2. Too Frequent Baths
I’m sure many of you find it desirable to give your cat a bath, at least sometimes.
Well, this isn’t necessary, especially with strictly indoor cats. Felines only need their humans to wash them in the case they’re old or incapable of properly grooming themselves.
Frequent baths can even harm your cat’s fur and make it look lumpy. This happens because chemicals in shampoos can disrupt the natural oils in a cat’s coat.
These oils make their coats look smooth and shiny. Frequent washing of your cat may disturb the delicate balance of their skin.
Therefore, you should only wash your feline friend in case your vet instructs you to do so.
Obesity is a common health problem among felines across the world.
D. Tarkosova and associates  indicate that up to 63% of pet cats are obese. Potential risk factors for obesity development are being male, neutered, middle-aged, fed treats, and housed-indoors.
Weight problems can significantly decrease a cat’s quality of life. It could also prevent it from proper grooming, causing its fur to become lumpy.
Here it’s necessary not to overfeed a cat or leave food available to it at all times. Regular physical activity is crucial for maintaining a healthy body weight in cats.
It sometimes can be tricky to define an appropriate amount of daily meals for a cat. If you have difficulties with this, you should ask your veterinarian for advice.
A cat whose fur has gone lumpy could be dealing with an underlying health problem that’s preventing it from doing its grooming routine adequately. One of these issues is arthritis.
This condition causes painful joints in a cat and makes moving feel uncomfortable for it.
• Reduced activity
• Hiding behavior
• Unwillingness to jump or go up or down stairs
• Stiffness in the legs
The veterinarian will need to undertake an X-ray to confirm arthritis in your cat. This condition is treated with pain management medications and non-steroidal anti-inflammatory drugs.
Although arthritis cannot be cured, a cat with adequate treatment can still live a quality life.
5. Dental Problems
Another health problem that could cause your cat not to groom its fur is dental issues.
The pain is making your cat uninterested in grooming. This can lead to a poor-maintained and lumpy coat.
Tooth resorption and gingivitis are among the most common dental problems in felines. Besides a lumpy coat, a cat could also show signs such as red gums, bad breath, appetite loss, and excess drooling.
As soon as you notice any of these, you should take your cat to the vet’s. It’s necessary to treat the dental problem and relieve its symptoms.
6. Bacterial Skin Infections
Bacterial skin infections are another potential medical reason behind a cat’s lumpy fur. Besides this sign, PetMD points out additional common symptoms of this health problem:
• Redness on the skin
• Opes sores or ulcers
• Discharge or blood from sores
• Skin odor
These infections can cause a cat to scratch its fur excessively, making it look worse.
Some of the most common bacterial infections among felines are caused by Staphylococcus pseudintermedius and Pasteurella multocid.
These infections are treated with antibiotics. Also, a vet could advise you to apply topical medications to your cat’s fur.
Food or environmental allergies are also a potential culprit of a cat’s lumpy coat. Other common clinical signs are sneezing and watery eyes, excess scratching, and open sores on their skin.
Itchiness due to allergies can get very bad in cats, causing them to scratch and even bite their fur.
This health problem can be treated in various ways. Some cats will benefit from oral antibiotics, while others will be prescribed with corticosteroid therapy.
In some cases, veterinarians prescribe anti-inflammatory topicals or allergen-specific immunotherapy.
8. Parasite Infections
Besides bacterial infections, a cat could also get parasite infections.
Different kinds of parasites can attack a cat. Some of the most common ones are ringworms, tapeworms, and hookworms.
These worms cause severe irritation and itching to a cat’s skin. This is why a cat starts to excessively scratch and bite the affected area, making its coat look lumpy.
Some cats also display severe appetite loss and gastrointestinal issues.
When a veterinarian determines the exact parasite infection in your cat, they will prescribe a dewormer medication.
If you’re worried about how to clean your house after discovering your cat has worms, you can find useful advice here.
9. Hormonal Conditions
A lumpy coat can also be a sign of hormonal imbalance in felines. Some of the most common hormonal conditions in cats are diabetes mellitus and hyperthyroidism.
Increased thirst is usually the most visible sign of diabetes in a cat. But, as Kingsdale Animal Hospital explains, a lumpy, unkempt coat is also a key symptom of this condition.
This often occurs because a cat’s body is deprived of energy, affecting both its coat and skin. Also, a cat with diabetes can become lethargic and uninterested in keeping its coat neat.
Feline diabetes is treated with insulin injections. Although it’s an incurable condition, a cat can still live a long and happy life.
Feline hyperthyroidism is a condition in which an overproduction of thyroid hormone occurs.
Cornell Feline Health Center points out how cats with this condition can manifest an unkempt and matted coat.
Hyperthyroidism is treated with dietary therapy, medications, and, in some cases, surgery. The last option includes the removal of the thyroid gland. Although this is a permanent solution, it involves general anesthesia which always brings a dose of risk.
Of course, any kind of hormonal condition in a cat requires urgent veterinarian assistance.
Why has my cat’s fur gone lumpy?
There are a couple of potential answers to this question. Tangles and fur can make a cat’s fur look lumpy, and this is especially common with long-haired felines.
Even though you think you’re doing your cat a favor by bathing it, you could potentially cause the lumpy appearance of its fur. Washing is usually unnecessary with healthy, young cats. By doing this frequently, you could actually disrupt its skin balance.
A cat that has problems with weight can be unable to groom, leading to a lumpy fur. Finally, different health problems can cause this problem in your cat, such as diabetes, skin infections, and hormonal conditions.
To prevent lumpy fur, it’s essential to regularly brush your cat’s coat. If you’re uncertain about the ideal frequency, our cat hair length chart provides useful information.
Finally, in case you doubt your cat has some health problem, contact your vet right away. This is the only way to be sure what exactly caused its fur to go lumpy all of a sudden.
 Tarkosova D, Story MM, Rand JS, Svoboda M. Feline obesity – prevalence, risk factors, pathogenesis, associated conditions and assessment: a review. Vet Med-Czech. 2016;61(6):295-307. DOI, Retrieved October 7, 2023.