Autoimmune diseases in pets: A vet-approved guide

The immune system provides vital protection against infectious illnesses and can also help to detect and destroy cancerous cells – yay! But did you know that sometimes the immune system can go off track and actually cause harm to our fur-babies? Yikes!

Autoimmune diseases are illnesses that are caused by the immune system acting abnormally; specifically, the immune system mistakenly targeting and attacking the body’s own healthy tissues. Depending on the tissues affected, these diseases can cause a range of symptoms, and in some cases can even be life-threatening.

Read on to learn more about autoimmune diseases and conditions in dogs and cats, including the different forms, common symptoms to watch for, and options for treatment.

What is an autoimmune disease?

Immune-mediated diseases are illnesses that are caused by some kind of abnormal functioning of the immune system. Autoimmune diseases are a subtype of immune-mediated disease, occurring when the immune system has somehow been triggered to attack the body’s own tissues or organs instead of just things that are actually harmful (like invading bacteria or viruses, or abnormal cancerous cells).

In some cases of autoimmune disease in pets, we may be able to pinpoint a particular initial trigger, such as cancer, exposure to certain parasites, or an unusual reaction to a particular toxin or drug – this is called secondary autoimmune disease. However, in many cases, we aren’t sure why a pet has developed an autoimmune condition – this is known as a primary or idiopathic autoimmune disease.

Autoimmune diseases may affect a single body system, or they can affect multiple body systems or organs at once.

Common autoimmune diseases in dogs

Autoimmune conditions in dogs can take many forms. Some of the ones you’ll most often hear about include:

Autoimmune conditions in dogs	What it is	Key symptoms	Breeds at risk
Immune-mediated haemolytic anaemia (IMHA)	Anaemia and unwellness caused by the dog’s immune system targeting and destroying its own red blood cells.	Pale gums, lethargy or weakness, increased breathing rate, potentially, jaundice (yellow discolouration of the skin, eyes and gums).	Cocker Spaniels, Poodles, Old English Sheepdogs, Irish Setters.
Autoimmune Hypothyroidism	A decrease in the production of thyroid hormone (which normally functions to help drive the dog’s metabolism), due to the immune system attacking the thyroid gland.	Unexplained weight gain, lethargy, getting cold easily, thinning fur or poor hair growth, increased susceptibility to skin and ear infections.	No specific breed predisposition.
Pemphigus Complex	A group of autoimmune diseases where the immune system attacks the connections between skin cells; the most common of which is Pemphigus Foliaceus (PF).	Hair loss, skin ulcers, crusts and scabs, particularly around the eyes, nose, ears, and head but also sometimes the footpads and body. Potentially also lethargy, fever and a reduced appetite.	Akitas, Chow Chows, Labradors, German Shepherds, Cocker Spaniels, English Bulldogs and Collies.
Immune-mediated thrombocytopenia (IMTP)	A bleeding disorder caused by the dog’s immune system attacking platelet cells that normally assist with blood clotting.	Spontaneous bruising, usually in small clusters that are most visible on hairless skin, the gums, and the whites of the eyes. Unexplained bleeding can also be seen from the nose or in urine, vomit or poo.	Cocker Spaniels, Poodles, and Old English Sheepdogs.

A vet’s perspective: The diagnostic journey

While some autoimmune conditions have fairly classic symptoms, others can be a little trickier to confirm due to varying symptoms or an overlap of their symptoms with other common diseases.

If your dog is suspected of having an autoimmune condition, we’ll usually have to run a number of tests to rule out other, similar conditions so we can confirm the diagnosis. For instance, a dog with symptoms of anaemia due to red blood cell destruction will usually need laboratory assessment of their red blood cells to confirm IMHA, but they will also ideally undergo other tests such as:

• General blood and urine tests to check their organs (as IMHA can affect the health of other organs such as the kidneys).
• Imaging of their chest and belly (such as x-rays and an ultrasound scan, or a CT scan), as IMHA can be triggered by cancers.
• Testing for certain infectious diseases that can trigger IMHA.

Once we confirm a diagnosis, we can then get cracking on providing the most appropriate treatment and support to your pet!

Common autoimmune diseases in cats

Cats experience many of the same autoimmune conditions of dogs. However, the most common autoimmune conditions that we tend to see in cats are:

Autoimmune conditions in cats	What it is	Key symptoms	Breeds at risk
Inflammatory bowel disease (IBD)	Long-term gut inflammation due to cells of the immune system entering the gut lining to fight off a perceived threat – this may be a particular food protein or bacteria, but the cause isn’t always clear.	Most commonly, recurrent vomiting. Frequent episodes of diarrhoea, which may contain blood or mucus, weight loss, flatulence and/or a rumbly tummy.	Siamese and other oriental breeds, but also Domestic Shorthairs and Longhairs (moggies).
Pemphigus Foliaceus	An autoimmune disease where the immune system attacks the connections between skin cells.	Pustules, ulcers and yellowish crusts, which usually develop around the face and ears, and then may spread to the toes, paw-pads, and sometimes the body. This can sometimes include the following: Fever Lethargy Reduced appetite Pain	Seen mostly in Domestic Shorthair/Longhair cats.

How vets treat autoimmune disease

Dogs and cats with autoimmune diseases can require long-term or even lifelong courses of medications to suppress their immune system – this is known as immunosuppressive therapy. They also often require additional supportive treatments until their signs of unwellness settle. Regular veterinary reassessments are required throughout their treatment due to the intensity of treatment required and the potential for relapses.

The cornerstone: Immunosuppressive therapy

The initial treatment for the more severe forms of autoimmune disease is prednisolone, a steroid medication. This is started at a high dose to suppress the activity of the pet’s immune system, and then once the disease process is under control, the dose is very gradually tapered down (over a period of weeks to months) to reduce side effects whilst still maintaining control of the pet’s disease.

In some cases, your furry friend may require more than one immunosuppressive medication to gain control of their symptoms.

Supportive care

Dogs and cats with autoimmune conditions can become very unwell, so may require intensive supportive care until their immunosuppressive treatment takes effect. For instance, pets with severe anaemia due to IMHA may require hospitalisation for oxygen supplementation, blood transfusions, and “blood-thinning” medications to prevent the formation of dangerous blood clots.

Some pets may also require lifelong management of their condition, such as a strict prescription hypoallergenic diet for dietary-responsive IBD.

The role of pet insurance in managing chronic illness

As well as their emotional toll, autoimmune conditions can be financially challenging for owners to manage. This is because pets with these conditions:

• Can become extremely unwell, requiring intensive and/or specialist veterinary care to support them through severe flare-ups.
• Often require long-term or even lifelong veterinary treatment.
• Usually require extensive diagnostic testing to confirm their condition (such as blood tests, infectious disease testing, surgical biopsies, and imaging) and then may require regular rechecks and diagnostic testing (such as blood tests) to monitor their response to treatment in the longer-term.

Ensuring your pet is covered by a comprehensive pet insurance policy can help to relieve the financial burden of managing any chronic illnesses or injuries, so you can focus on caring for your furry family member. Be sure to check your policy documents to see what is and what isn’t covered as your insurer may not cover pre-existing conditions.

Autoimmune diseases in dogs can be complex and sometimes overwhelming for pet owners to understand. To help provide clarity, we’ve put together answers to some of the most common questions about these conditions, their treatment, and what to expect when managing your dog’s health.

If your pet has been diagnosed with an autoimmune disease, remember – it doesn’t mean they can’t live a happy, healthy life. With the right treatment and veterinary support, many pets can manage their condition and thrive.

Having a suitable pet insurance policy in place may means that you’re covered for unexpected vet bills that sometimes come with managing chronic health conditions. Learn more about Buddy Pet Insurance and the different levels of cover available to see if it’s an option for you and your four-legged family member.

Frequently asked questions ( FAQsFrequently Asked Questions )

Can autoimmune disease in dogs be cured?

Most pets with an autoimmune disease will require at least 3-6 months of treatment. Some may gradually be able to be weaned off their immunosuppressive therapy under veterinary supervision, although relapses in their condition are possible. Certain conditions, however (such as inflammatory bowel disease), require life-long management.

What causes autoimmune disease to flare up in pets?

The exact cause of autoimmune disease is not fully understood, though it is thought to be a combination of genetics and environmental factors that trigger inflammation, such as allergens, pollutants, infections, or unusual reactions to certain drugs.

Is autoimmune disease contagious to my other pets or my family?

No, autoimmune diseases are not contagious.

What is the most common autoimmune disease in dogs?

The most common autoimmune disease in dogs appears to be immune-mediated haemolytic anaemia, although immune-mediated thrombocytopenia, some forms of Lupus Pemphigus Foliaceus and IBD are seen relatively frequently also.

4 Nov 2025