Mastocytosis in Dogs

Mastocytosis in Dogs
June 12, 2019

Mastocytosis in Dogs


 Mastocytosis in dogs can be a worrying condition, however, it is not untreatable. The first step to managing your dog’s condition is making sure that you know everything about the condition, so you are adequately prepared to help them through their recovery.

What do Mast Cells Do? 

Mastocytosis is also referred to as mast cell tumours in dogs. The mast cells are the cells in ours and your dog’s bodies which are found in the connective tissues. The connective tissue which is most affected is the connective tissue which is closest to external areas on the dog’s body such as the nose, mouth, skin and lungs. However, mast cells can also come from bone marrow too. 

It is the job of mast cells to provide a defence against everything from tissue repair and parasitic infections. Mast cells also help to form new blood vessels and help your dog to deal with allergic reactions. 

The mast cells are made up of a number of different chemicals, some of these chemicals have a direct biological impact on inflammation and immune systems.


How Dangerous are Mast Cell Tumours? 

How dangerous a mast cell tumour is depends on its location in your dog’s body, the level of the inflammation, and the differentiation of the tumour. Differentiation essentially indicates how much of a mast tumour appears like a normal healthy cell – the more differentiated it is, the more it will appear like a normal cell. This means that the more differentiated it is, the better the prognosis for your pet will be. 

Grade one cells have a low risk of metastasis. 

Grade two cells have the potential for locally invasive metastasis 

Grade three cells come with a high risk of metastasis and the cells will be poorly differentiated or entirely differentiated. 

So, essentially, there are three different stages, but the impact on your dog’s health will need to be determined by your vet through testing. The advice we’ve given here should not replace your vet’s guidance and treatment when it comes to Mastocytosis in dogs

Some breeds are more susceptible to mast cell tumours than others. Looking at recent diagnoses it is Boston Terriers, Pugs, Bulldogs and Boxers who are most at risk. Most people buying dogs don’t even know to ask the breeders about the history of Mast Cell Tumours with the dog’s parents – however, thankfully, people are becoming more aware of the condition. 

Mast cell tumours can affect a dog at any stage of its life, it is not unheard of for dogs to be diagnosed with this condition under the age of one. However, dogs are typically diagnosed with this condition at the age of 8 years old. 


 Types of Mast Cell Tumours and Mastocytosis in dogs

As we mentioned earlier, depending on where the Mastocytosis is in your dog’s body, the severity of the disease will vary. This means that the symptoms will also vary. Here’s what you should look out for: 

  1. Tumours appearing on the skin or underneath the skin which have been present for a number of days. 
  2. Tumours which change routinely in size 
  3. Tumours which rapidly grow after a period of non-growth 
  4. Fluid build-up and redness on a skin tumour 
  5. Skin conditions which look like other issues such as insect and flea bites, allergic reactions, and warts 
  6. The presence of multiple skin masses on your dog’s body at the same time.
  7. Enlarged lymph nodes around the site of the tumour
  8. Signs that your dog’s skin is inflamed or itchy 
  9. Tests may show that your dog’s spleen and livers are enlarged. 
  10. Vomiting 
  11. Upset stomach 
  12. Loss of appetite

Causes of Mastocytosis in Dogs

Sadly, no one knows the exact cause of Mastocytosis in dogs. However, with more and more research being done on the condition every year, it is looking likely that we will see plenty more information on the disease and prevention in the coming years. 

Diagnosing Mastocytosis in Dogs

If you suspect that your dog may have mast cell tumours, you’ll need to take your dog to the vets and give them a full history of your dog’s health. You may want to keep a note of all of the background history on the symptoms in terms of timelines and severity. This information will give your vet valuable information on which of your dog’s organs are affected by the mast cells. 

After a physical once over, your vet with perform a diagnostic test by taking cells from one of the suspected tumours. This process will be relatively painless and won’t require an anaesthetic. This test will show if there are any abnormal cells in the sample. 

If abnormalities are detected, a full biopsy will be required. This test will show which stage the mast cells are in the disease. Your vet may also need to take some lymph node samples for further investigation. This may be from your dog’s kidney, spleen, or bone marrow. 

If tumours are affecting your dog’s chest or abdomen, ultrasound images or X-rays may need to be taken. 

Treatment of Mastocytosis in dogs

 Your vet may choose to treat the disease with antihistamines, this will prevent cells being released from the tumour from entering into the bloodstream. This treatment may need to be paired with surgical intervention. However, the first thing your vet will want to prevent is an excess amount of histamines entering the rest of your dog’s body. 

If your dog needs to undergo surgery, the tumour will be removed along with the surrounding tissue. Whether this is the best option for your dog depends on the results of microscopic evaluation of the tissue which will be removed. In some instances, the tumour will need to be removed as soon as possible. Your dog’s lymph nodes may need to be surgically treated too. In severe cases, your dog may need chemotherapy which will prevent the future development of mast tumour cells. Chemo can also give your dog brief respite from the disease if the primary tumour cannot be removed.

Radiotherapy is also another option to reduce the size of the tumour if your vet is not able to remove the primary tumour. 

After any mast cell chemotherapy or surgery, your dog will need between 1 to 4 months of recovery.