Why is My Cat's Belly Swollen and Hard?

By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: February 6, 2020
Why is My Cat's Belly Swollen and Hard?

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Unlike dogs, most cats do not like having their belly rubbed. This is because their underside feels vulnerable. Only cats with high levels of trust in their guardians will let this happen. For this reason, it can be difficult to determine the condition of their belly. However, even if it may be difficult, we need to take a look if we suspect a problem with our cat's belly. The reason is because a cat with a swollen or hard belly might have a serious health problem. It may be a sign of internal parasitosis, hyperadrenocorticism or even something life threatening.

The reason this AnimalWised article looks into the causes of why your cat's belly is swollen and hard is to help prevent and treat these potential problems. As always, visiting a veterinarian to achieve the right diagnosis is necessary.

You may also be interested in: Why is My Dog's Belly Hard

My kitten has a swollen belly

Due to their lack of developed immunity, a swollen kitten belly is particularly worrying. They are more vulnerable to disease and infection than an adult cat. Perhaps the most common cause of a hard or swollen belly in kittens is internal parasites. If you pick the kitten up, you may be able to see they have a distended abdomen.

A kitten will be infested with parasites in one of two main ways. Firstly, their environment may not be hygienic enough. For this reason, we need to ensure the nest where the mother gives birth is clean and other animals are prevented from entering it. This should continue until the kittens are fully weaned. The other way kittens may become infested is due to parasites coming from the mother during feeding. It is possible the mother will be asymptomatic, but the vulnerable kittens are unable to fight them off.

If we suspect a kitten's abdominal enlargement is due to internal parasites, we need to take them to the veterinarian immediately. They will be able to perform the correct diagnostic tests to not only confirm the presence of parasites, but to determine which type. Different types of parasite require different treatment methods. After treatment, the veterinarian will also be able to advise us on the proper course of deworming. This should be implemented at the same time as their vaccination schedule.

If your kitten has a swollen belly and also exhibits diarrhea, then the parasites in their digestive system will be considerable. If we see blood or the worms themselves in their feces, then immediate action needs to be taken. The vet will likely take a sample of the feces and examine it under a microscope to see what we are dealing with. Once the type of parasite is identified, they will be able to prescribe the right course of treatment.

You may need to consider that the parasite may not be visible in one single sample, so several samples over alternate days may need to be taken. In any case, a heavy parasitical infestation in kittens is particularly dangerous. The profuse diarrhea dehydrates them and endangers their life.

Lastly, a bloated belly in kittens may not necessarily be a problem. When they feed, their small stature means their abdomen will become distended as it is full of milk. This will reduce as their metabolize their food. The belly will be temporarily bloated, but it will not be hard.

Swollen and hard belly in cats with ascites

Ascites is the medical term for certain types of abnormal fluid accumulation in the abdominal cavity. There are various causes of ascites, but veterinary examination is required to identify and treat it effectively. Ascites can explain why our cat has a swollen and hard belly, but this is a symptom of another condition. To know the underlying cause of a swollen abdomen in cats, we need to look at the causes of ascites.

Infectious peritonitis causing hard bellies in cats

Feline infectious peritonitis, also known simply as FIP, is one of the most serious diseases which can cause a cat's belly to swell and harden. It is a viral pathology which causes inflammation in the peritoneum, the membrane which lines the inside of the abdomen. This is related to the feline coronavirus as it is a mutation of feleine enteric coronavirus.

FIP can also affect certain organs such as the liver or kidneys. As is the nature of a virus, it is very difficult to treat the infection directly. Instead, the symptoms are treated and the immune system is boosted in order to fight off the infection. As this disease is so infectious in cats, a vaccine has been created to prevent it.

Ascites is not the only symptom which accompanies feline infectious peritonitis. Other symptoms include:

  • Chronic fever
  • Anorexia
  • Weight loss
  • Lethargy
  • Excessive thirst and urination (if kidneys are affected)

The symptoms will vary depending on the organs affected. Respiratory problems can occur if the fluid accumulation affects the lungs, specifically pleural effusion. Jaundice and neurological problems can also manifest.

Why is My Cat's Belly Swollen and Hard? - Infectious peritonitis causing hard bellies in cats

Abdominal inflammation in cats due to liver tumors

The presence of a tumor or tumors in the liver is another cause which may explain why a cat has a swollen or hard belly. This disorder is more common in older cats. In these cases, older cats will usually show other non-specific symptoms, i.e. those which are common to several diseases. Concurrent symptoms usually only occur when the damage is already advanced.

When the cat has abdominal distension due to tumors, the belly area either enlarges or becomes loose and flabby. The tumor is a rigid mass which means the cat's stomach feels hard. We might also see other symptoms such as:

  • Anorexia
  • Weight loss
  • Lethargy
  • Increased urination
  • Vomiting

Only the vet can give an accurate diagnosis, especially because many of these symptoms also present with various diseases. The prognosis will depend on the individual and whether the tumor is malignant or benign.

Abdominal inflammation in cats due to hyperadrenocorticism

Although not very common, hyperadrenocorticism could be the root cause of a cat's swollen belly. This disease is also known as Cushing's syndrome and is caused by an excess of glucocorticoid production, usually due to tumors or hyperplasia. It requires veterinary treatment and regular follow-up.

Other symptoms may include:

  • Lethargy
  • Increased food intake
  • Increased water intake
  • Increased urination
  • Hair loss
  • Fragile skin

When hair and skin is affected, it is likely the condition is in an advanced stage and treatment is more difficult. They will also become very weak and frail.

Why is My Cat's Belly Swollen and Hard? - Abdominal inflammation in cats due to hyperadrenocorticism

Other reasons for abdominal inflammation in cats

In addition to the causes of a swollen belly already mentioned, there may be some other issues affecting the cat:

  • Labor: if a pregnant cat is in labor, the cat will need to use contractions to birth the kittens from the uterus. This can give the impression that the belly has temporarily inflamed.
  • Uterine problems: there are infections such as pyometra which cause the uterus to swell. These can be seriously life threatening and need immediate treatment.
  • Obesity: of course a cat with an enlarged belly might have a more simplistic cause. In the case of overeating or eating food which is too rich, they may develop obesity. However, you will see they will also put on weight on other parts of the body.

As we said in the introduction, being able to feel your cat's belly to see if it is swollen is not always an easy task. This is why it is so important to look out for related symptoms and to have regular veterinary check ups.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Why is My Cat's Belly Swollen and Hard?, we recommend you visit our Other health problems category.

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What did you think of this article?
My vets they don't notice her swollen belly say theres no problem but I notice there is a problem,there not doing much about it really she looked like this for a long time since a kitten she's now 6 years old.
Administrador AnimalWised
Hi Crystal,

Have you addressed this with the veterinarian? While going to the vet is always the best option, it is possible something can be missed. However, it is also possible they have another explanation. For example, it is possibly a primordial pouch:
George & Mercele Rambow
My cat has for 2 or 3 years had swollen stomach eat small meals often throws up to much been thin since a baby cat has been thin for a long time.
Administrador AnimalWised

Have you spoken to a veterinarian about this problem?
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