Low Platelet Count in Dogs: Thrombocytopaenia in Dogs: Causes, Symptoms, and Care

Thrombocytopaenia, also known as thrombocytopenia, occurs when a dog has abnormally low levels of platelets in the blood. Platelets (also called thrombocytes) are essential for normal blood clotting, so when their numbers fall significantly, the dog’s ability to stop bleeding is impaired. This can range from a minor finding on a routine blood test to a life-threatening emergency.

Causes of Low Platelet Count in Dogs

There are several categories of cause:

• Immune-mediated thrombocytopenia (IMT): One of the most common causes, where the dog’s immune system mistakenly destroys its own platelets. It can occur on its own (primary IMT) or secondary to another condition such as infection, cancer, or another immune disease.
• Tick-borne diseases: Ehrlichia and Anaplasma are tick-borne infections that are a significant cause of low platelet counts in dogs, particularly in areas where ticks are common.
• Infections: Various bacterial, viral, and protozoal infections can reduce platelet counts directly or trigger immune-mediated destruction.
• Drug reactions: Certain medications can cause thrombocytopenia as a side effect.
• Bone marrow disorders: Conditions that reduce the production of blood cells in the bone marrow, including aplastic anaemia or myelosuppression from chemotherapy, can reduce platelet production.
• Disseminated intravascular coagulation (DIC): A serious condition in which clotting occurs throughout the bloodstream, consuming platelets rapidly.
• Splenic pooling: An enlarged spleen can sequester large numbers of platelets, reducing the circulating count.

Symptoms of Low Platelet Count in Dogs

Signs vary with the severity of the thrombocytopenia and may include:

• Petechiae or ecchymoses (tiny pinpoint red spots or larger bruised patches on the skin or mucous membranes)
• Prolonged bleeding from minor wounds
• Nosebleeds or bleeding from the gums
• Blood in urine or faeces
• Lethargy and weakness
• In severe cases, spontaneous internal bleeding

Diagnosis and Treatment

Diagnosis involves a full blood count, examination of a blood smear, and further testing to identify the underlying cause (such as tick-borne disease panels or bone marrow assessment). Treatment depends on the cause: immune-mediated disease is typically treated with immunosuppressive drugs such as corticosteroids, while other causes require specific treatment. Blood or platelet transfusions may be used in severe cases to stabilise the dog while underlying treatment takes effect.