ITP in Dogs: Through the Eyes of a Veterinarian and Dog Mom

ITP in dogs can be a scary diagnosis but it doesn’t have to keep your dog from living a great life. Take it from Dr. Laura Garlow, veterinarian and mom to Fletcher, a Goldendoodle who lived with ITP for nine years. On the invitation of integrative veterinarian Dr. Julie Buzby, Dr. Garlow takes a comprehensive look at ITP in dogs and shares her experience walking this path with Fletcher.

I think that everyone’s first dog as a “grown-up” holds an extra special place in their heart. That was the case for me and Fletcher. I like to affectionately call Fletcher the “best bad dog” in the world. No other dog will ever be able to fill the Goldendoodle-sized hole he left in my heart when he passed away a little over a year ago at the respectable age of 11. He had a long happy life, nine years of which he lived with immune-mediated thrombocytopenia, but it still never feels like long enough.

My now-husband (who was my fiancée at the time) and I picked Fletcher up as a rambunctious ball of fluff the summer before I started veterinary school. I wanted to make sure I did everything right. So I spent that summer reading all the puppy training manuals I could and hiding everything chewable in our little apartment.

Fast forward a couple of years and Fletcher had turned into a pretty great dog. Maybe the puppy training manuals I poured over so carefully had worked. Or maybe he was just destined to have a wonderful temperament. Regardless, he was a good boy and he brought us so much joy.

Tiny signs of an issue with blood clotting

My husband and I got married during the summer between my second and third year of veterinary school. While on our honeymoon, we boarded Fletcher at a doggy daycare that he loved. He had a blast playing with his doggy friends but had gotten a little scruffy. So when we got home, I gave him a bath, dried him off, and brushed him out. He was his normal self at that point. But just a couple of hours later, I noticed that the insides of both of his ears were covered with tiny pin-prick red dots where I had brushed him.

While I was only halfway through my veterinary education, I knew enough to know that this was not normal. With a bad feeling in the pit of my stomach, I quickly texted a picture to a close friend and mentor. He confirmed my fear that the tiny pin pricks looked like petechia, or very small bruises. Then he gently reminded me that petechia are evidence of an issue with blood clotting. This meant we needed to have some lab work performed ASAP to try to pinpoint the problem.

Since Fletcher was otherwise feeling well with no other evidence of bleeding or bruising, we decided that it was okay for me to wait to take him into the clinic until first thing the following morning. I didn’t sleep a wink that night.

A diagnosis of ITP, immune mediated thrombocytopenia

We went into the clinic the next day. A couple of blood tests later and just like that, Fletcher had been diagnosed with immune mediated thrombocytopenia, or ITP.

This diagnosis had a profound impact on our family, and on my career. I developed a special interest in internal medicine and immune-mediated diseases. This interest led me to complete an intensive one-year internship at a specialty and emergency veterinary hospital after graduation. I found that I enjoyed the challenge of complicated medical cases, and I especially enjoyed helping pet parents understand and navigate the challenging situation of having a hospitalized pet.

After my internship, I spent many years at the same specialty hospital caring for sick hospitalized patients. In that time, I treated many wonderful dogs with immune-mediated thrombocytopenia. Through the years, I have learned so much about this condition, both from our experience with Fletcher, and from my experience caring for my patients. I want to share some of my knowledge with you.

If your beloved dog has been diagnosed with ITP, I hope you finish this article feeling empowered with the knowledge you need to face this challenge head-on.

What is ITP in dogs?

Immune mediated thrombocytopenia (ITP) is one of several autoimmune diseases in dogs. In ITP, the dog’s own immune system attacks and destroys his or her platelets. As a result, the dog has thrombocytopenia, which is the fancy medical term for a low platelet count.

Platelets 101

Platelets are tiny cell fragments within the blood. They are made in the bone marrow and are vital to blood clotting. You may think about platelets helping stop bleeding from a large cut or wound, but platelets aren’t just there for the primetime trauma. They also prevent life-threatening bleeding from normal daily microscopic wear and tear to blood vessels. When these tiny tears occur, platelets clump together at the site of the damage to form a blood clot. This stops any bleeding before you would even be able to notice there was an issue.

Normal platelet counts vary depending on the laboratory equipment being used to measure their levels. Generally speaking, a normal platelet count is anywhere from about 180,000 to 500,000 platelets per microliter of blood. Most of the time, there are no signs of ITP until the platelet count dips below about 40,000 platelets per microliter of blood. At that point, the risk of spontaneous bleeding sets in.

Occasionally, dogs are diagnosed with ITP due to a moderately low platelet count found by accident on routine yearly bloodwork. However, it is much more common for dog parents to have no idea there is a problem until the platelet count is less than 10,000 platelets per microliter and their beloved companion starts showing obvious signs of bleeding.

What are the symptoms of ITP?

The clinical signs of ITP can be broken into three main categories:

1. Direct signs of bleeding or bruising

• Small pinpoint bruises on the skin or mucous membranes (i.e. petechia)
• Larger bruises on the skin or mucous membranes (i.e. ecchymosis)
• Blood in the urine (i.e. hematuria)
• Dark, black, or tarry stool (i.e. melena)
• Fresh red blood in the stool (i.e. hematochezia)
• Blood in vomit that can appear like coffee grounds ( i.e. hematemesis)
• Nose bleeds in dogs (i.e. epistaxis)
• Bleeding into the whites of the eyes (i.e. scleral hemorrhage)

2. Signs related to anemia in dogs (i.e. low red blood cell count) from losing too much blood

• Pale or white gums
• A lethargic dog
• Decreased appetite
• Exercise intolerance
• Rapid heart rate
• A dog who is breathing fast
• Collapse

3. Signs related to the body system where bleeding has occurred

• Blindness from bleeding into the back of the eye (retinal hemorrhage)
• Dog seizures or other neurologic signs from bleeding in the brain
• Difficulty breathing from bleeding into the lungs

If you notice any of these signs, please make an appointment with your vet immediately. In some cases, severely affected dogs may need an emergency vet visit .

How does the vet reach an ITP diagnosis in dogs?

At the appointment, your veterinarian can check your dog’s number of platelets on the in-house laboratory equipment as part of a complete blood count (CBC). Since low platelets are the primary characteristic of ITP, a platelet count is the diagnostic tool of choice.

The CBC will also allow your veterinarian to check your dog’s red cell count. This is important as anemia can be present due to bleeding from ITP. Or sometimes ITP is combined with immune-mediated hemolytic anemia (IMHA in dogs). Evan’s Syndrome is the name for ITP and IMHA in dogs.

Occasionally platelets can clump together and read as falsely low with in-house machines. This means that in most cases, your veterinarian will want to confirm the low platelet count by looking at a blood smear underneath a microscope.

The vet will also take into consideration your dog’s age, gender, and breed when diagnosing ITP. Any dog can have immune-mediated thrombocytopenia, but like most conditions there are some dogs who might be more predisposed. Many auto-immune conditions are more common in females, and ITP follows that trend too. Middle-aged dogs are the age group most likely to have ITP. Some breeds have a higher risk as well. These include Poodles, Cocker Spaniels, and Old English Sheepdogs.

Once the vet has determined your dog has ITP, he or she will start looking for the underlying cause, if there is one.

What causes ITP in dogs?

When veterinarians think about ITP, they break it into two classifications—primary and secondary. Primary ITP (i.e. idiopathic ITP) is a diagnosis of exclusion. This means the vet will use additional diagnostic testing to rule out the presence of a trigger. If the vet doesn’t find a clear cause, he or she will categorize it as primary ITP.

Secondary ITP occurs when another medical condition triggers the immune system to run amok within the body, attacking its own cells. Common triggers of secondary ITP include:

Infections

Almost any infection can over-stimulate the immune system and trigger autoimmune disease. However, there are some infections where this is a much more common occurrence than others. Fleas and ticks spread many, but not all, of these infections.

Some of the more common infectious triggers of ITP include:

• Tick-borne disease in dogs such as Ehrlichia, Rocky Mountain Spotted Fever, or Babesia
• Bartonella
• Mycoplasma
• Leishmania
• Leptospirosis
• Heartworm disease in dogs
• Systemic fungal infections

Drugs or vaccines

• Sulfa drugs
• Cephalosporins

Note: While vaccines were once thought to be a common trigger for immune-mediated diseases like ITP, more recent studies have not supported this link. In general, vaccines are safe and do a great job of protecting your pet from preventable illness. If you are wondering which dog vaccines are absolutely necessary, I recommend having an open conversation about your concerns with your veterinarian.

Cancers

• Lymphoma in dogs
• Leukemia
• Multiple Myeloma
• Histiocytic Sarcoma
• Hemangiosarcoma in dogs

How do you find the underlying cause?

To look for these triggers, your veterinarian will study your pup’s medication and vaccine history, ask you questions about preventative medications and lifestyle, and run additional diagnostic tests.

Your vet may perform a more limited in-house test for some common tick-borne infections. Alternatively, more comprehensive tick panels are available through outside veterinary diagnostic laboratories. In some cases the vet may decide to start a course of the antibiotic doxycycline while awaiting these results because doxycycline is effective against many tick-borne diseases.

To look for any underlying evidence of cancer, your veterinarian will likely recommend full lab work. He or she may also recommend chest and abdominal radiographs or even an abdominal ultrasound.

Fletcher’s ITP trigger

In Fletcher’s case, he had not been on any recent medications and we were diligent about giving him his flea, tick, and heartworm preventative medications. His chest radiographs were normal. Since I had access to internal medicine specialists at my veterinary school, we also performed an ultrasound and a more comprehensive infectious disease panel a few days later. Thankfully, Fletcher’s ultrasound did not show any evidence of cancer.

When the infectious disease panel came back, we were surprised to discover that Fletcher was positive for Bartonella, an infection that is spread via fleas and can sometimes trigger ITP. We treated Fletcher’s Bartonella infection with a course of antibiotics and crossed our fingers.

Many times, if you treat the underlying trigger, the ITP can resolve. However, this was unfortunately not the case for Fletcher. His ITP did not go away, but with the help of daily medications, he managed to have a wonderful life.

What is the treatment for ITP?

After reaching a diagnosis of ITP, the veterinarian will propose a treatment plan. It may involve:

Immunosuppressive medications

An out-of-control immune system is the root problem with ITP. So you would be correct if you guessed that medications to suppress the immune system are the mainstay of treatment. Steroids like prednisone for dogs are almost always part of the arsenal. However, the vet may also add on other secondary immunosuppressive medications like cyclosporine, mycophenolate, or azathioprine.

Vincristine

If your furry friend ends up needing to be hospitalized for ITP, your veterinarian may talk to you about a medication called vincristine. This is an injectable chemotherapy medication. Since it is given at a lower dose for dogs with ITP, side effects are rare. Vincristine functions to push any leftover tiny platelet fragments out of the bone marrow and into circulation. Studies have shown that dogs who receive vincristine have slightly shorter hospital stays due to a more rapid increase in their platelet count. 

IVIG

Intravenous Immunoglobulin (IVIG) is a more intensive treatment option that veterinarians usually reach for in severe cases or if a patient is not responding to more standard therapy. It is a human product and can be quite expensive, making it cost prohibitive for many pet parents.

IVIG essentially works by neutralizing the immune system cells by clogging up the site where they would bind to the platelets they were planning to inappropriately destroy. It is an injectable medication that must be given in the hospital as an infusion. IVIG can be a good option for some situations, and is generally well-tolerated. However, it is not a common day-to-day medication in the arsenal against ITP.

If you are interested in learning more about vincristine and IVIG, a study published in the Journal of Veterinary Internal Medicine compared these two options in dogs with ITP.

Blood products

Some dogs with ITP experience significant blood loss since they cannot mount an effective clotting response. If dogs lose enough blood that they are experiencing clinical signs from their anemia, they may need a blood transfusion. Packed red blood cell transfusions are the most common type of blood transfusions performed in veterinary medicine. These transfusions don’t provide any platelets or stop the bleeding, but they do stabilize the patient to buy more time for the medications to stop platelet destruction.

In some cases, veterinarians may reach for a whole blood transfusion to help with anemia and ongoing life-threatening bleeding. Whole blood contains both red blood cells and platelets, but unfortunately the platelets in the transfusion last for an incredibly short time inside the body. They may very temporarily help with severe bleeding, but this effect is short-lived. Unfortunately, a whole blood transfusion will not lead to an increase in platelet count.

Since ITP destroys platelets, it would seem like giving the dog more platelets would be a good treatment option. However, while platelet transfusions are relatively common in human medicine, they aren’t that useful in dogs with ITP. Two issues are at play in this situation. The first is that canine platelet products have somewhat limited availability. The second and more significant issue is that the platelets, once transfused, will be destroyed within hours by the same abnormal immune response that is destroying the dog’s own platelets.

Other supportive care

If your beloved pup is diagnosed with ITP, your veterinarian may add in other supportive medications to help treat specific symptoms. These may include:

• Antacids or stomach coating medications if your dog is experiencing gastrointestinal bleeding.
• Antinausea medications if your dog is nauseous.
• Appetite stimulants for dogs if your dog is not eating.

Your veterinarian will work closely with you to tailor the medication and treatment plan to your furry family member’s specific situation.

What is the prognosis and survival rate for dogs with ITP?

Using the treatment options we just discussed, the short-term prognosis for ITP Is good. The overall survival rate is roughly 80 to 85%. Unfortunately, though, this does mean that 15 to 20% of dogs pass away or are euthanized due to ITP.

There are a couple of factors that have been linked to a lower survival rate for some dogs with ITP. These include bleeding from the GI tract and an elevation in a blood marker known as BUN. If your pup falls into one of these categories, instead of losing hope, I recommend specifically talking to your veterinarian about your worries and discussing ways to tailor your dog’s treatment to his or her specific clinical situation.

The ups and downs of ITP treatment

One of the harder things to counsel clients on during treatment for ITP is the very normal, but understandably anxiety-inducing waiting game. It can take anywhere from four to seven days on average for immunosuppressive medications to kick in. During that time, we often check the platelet count and red cell count on a daily basis.

It can be very disheartening for dog parents to see that platelet count go from 8,000 to 5,000 to 5,000 again, especially if their dog is showing signs of bleeding. However, it is important to understand that just because a dog hasn’t responded over the first few days, doesn’t mean they still don’t have a good chance of responding positively to their medications.

Indications of improvement

You can breathe a sigh of relief when your dog’s platelet count increases above about 40,000 platelets per microliter. This is generally when your veterinarian will consider your dog to be out of the woods. At this level, life-threatening spontaneous bleeding is much less likely. Even so, you will want to treat your dog as if he or she is quite fragile until the platelet count increases back into the normal range.

This means no running or jumping or boisterous play. I even tend to recommend soft or canned food to decrease the risk of bleeding from the gums while waiting for the platelet count to normalize.

Happily, once the platelet count begins to rise, it normally continues to do so very quickly. Your veterinarian will likely want to monitor the platelet count every several days until it is normal. Once the platelet count has been in the normal range for three to four weeks, then the first step is to gradually reduce the dose of the steroid medication (often prednisone).

The vet typically decreases the dose by about 25% every three to four weeks while continuing to monitor to ensure the platelet count does not start to drop back down. If a secondary immunosuppressive agent was part of the treatment regimen, the vet will decide whether or not to stop or wean that medication once he or she is able to get the dog off steroids.

Medication side effects

Vets aim to taper the steroid dose first because while steroids are potent and effective medications to suppress the immune system, they do come with a number of side effects. Being able to use lower doses of steroids can be one of the advantages of adding in a secondary immunosuppressive medication.

All dogs are susceptible to experiencing steroid side effects, but large and giant breed dogs tend to be most sensitive. Some of the side effects you might see with chronic, high-dose steroid administration include:

• Increased thirst in dogs and increased urination
• Increased panting
• Lethargy or listlessness
• Weight gain, especially for small to medium-sized dogs
• Weight loss and significant loss of muscle mass, especially for medium to larger breed dogs
• Pot-bellied dog appearance
• Increased appetite
• Increased risk of other infections (skin infections, UTIs in dogs, etc.)
• Thinning of the skin
• A thin or dull haircoat
• Insulin resistance, which may increase the chances of diabetes mellitus or cause issues in an already diabetic dog
• Iatrogenic Cushing’s disease in dogs

If you think your dog’s steroid side effects are becoming problematic, speak to your veterinarian. He or she may be able to adjust your dog’s medications to reduce or eliminate some of the side effects.

What to expect long-term

Because of these side effects, vets always hope that we will be able to wean our ITP patients off all of their medications. That is possible in many cases. However, approximately one-third of dogs will have a relapse of their ITP either during their medication tapering or at a later date.

Sometimes it can be harder to get these dogs back into remission, but often they do still respond well to immunosuppressive medications. In some cases, dogs end up on life-long immunosuppressive medications to keep their ITP at bay. The vet will always try to get them on the lowest doses of medications that both control their disease and minimize their side effects.

Fletcher’s long and happy life with ITP

I can’t end this article without telling you what happened to Fletcher. He responded well to his medications and went into remission quickly. Happily, he never ended up needing a stay in the hospital or any blood transfusions.

A couple of months after weaning off his medications, a routine recheck revealed a significantly decreased platelet count. This indicated a relapse, which of course we felt disappointed about. He responded well again but his platelets dropped once more as we got him on the lowest doses of medications. This meant that he fell into the camp of dogs who need lifelong immunosuppressive medications to keep their disease at bay.

We bought a pill organizer, and we were diligent about giving his medications every day and keeping up with his routine rechecks. He experienced some side effects of the long-term steroid use including having to pee more often and losing a lot of his muscle mass. Luckily, at this point I was working at a specialty hospital. The internal medicine specialists were great about giving me lots of advice on his care.

We switched up his medication cocktail and found the right combination of medications that kept him in remission but also minimized his side effects. He lived a very happy life on those medications for more than six years.

Fletcher’s legacy lives on

Fletcher’s happy-go-lucky nature was both a blessing and a curse because by the time he started to act sick from cancer (unrelated to his ITP), it was already in his liver, spleen, and bones. We kept him as comfortable as we could and fed him lots of tasty, previously off-limits foods. Then we let him go when he told us it was time.

We still miss him very much, but we have so many wonderful memories with him. I am grateful for all the lessons he taught me, both about navigating a diagnosis of ITP and about how to empathize with dog parents when they are dealing with a complicated medical condition in their beloved companions. I hope that if you are facing a diagnosis of immune-mediated thrombocytopenia with your beloved dog, this article and Fletcher’s story give you the knowledge and the hope you need to make it through to the other side.

Has your dog been diagnosed with ITP?

What words of advice do you have for other dog parents who find themselves in a similar situation?