Petechiae

Petechiae are small, pinpoint, red or violet spots on the skin or mucous membranes of a dog, caused by bleeding under the skin. These spots are not palpable and do not fade when pressed. Petechiae indicate that small bleedings from capillaries (the smallest blood vessels) have occurred. They often point to a coagulation disorder or a serious health problem and should therefore be examined by a vet.

Causes of Petechiae in Dogs

Several possible causes for petechiae in dogs come into question. The most common include:

Thrombocytopenia (Deficiency of Platelets)

Platelets are responsible for blood coagulation. A deficiency in platelets leads to bleeding, which can manifest as petechiae. Causes of thrombocytopenia include:

• Autoimmune diseases (e.g., immune-mediated thrombocytopenia)
• Infections (e.g., tick-borne diseases such as Anaplasmosis or Ehrlichiosis)
• Medications that impair the production or function of platelets

Coagulation Disorders

Petechiae can occur with impaired blood coagulation. Possible causes:

• Hereditary coagulation disorders (such as von Willebrand disease)
• Poisoning (e.g., by rat poison, which inhibits coagulation factors)
• Liver diseases that reduce the production of coagulation factors

Infections

Severe infections can lead to petechiae if they damage the blood vessels or the immune system:

• Sepsis (severe blood infection)
• Viral infections that damage blood vessels

Trauma or Mechanical Stress

Severe coughing, vomiting, or collapse due to physical exertion or an accident can lead to petechiae, particularly in the mucous membranes of the eyes or mouth.

Poisoning

Toxins from certain plants, medications, or chemicals can lead to vessel damage and cause petechiae. Rat poison (anticoagulants) is a common example, as it inhibits blood coagulation and leads to bleeding.

Neoplasms (Tumours)

Tumours in the blood or bone marrow, such as leukaemia, can impair platelet production and blood coagulation, which can lead to petechiae.

Symptoms of Petechiae

Petechiae appear as small, pinpoint, red or violet spots on the skin or mucous membranes. They are generally flat and do not fade when pressure is applied. Often, additional symptoms occur simultaneously that point to the underlying condition:

• Bleeding from the gums, nose, or eyes
• Blood in urine or faeces
• Weakness, lethargy, or loss of appetite
• Swelling or bruising
• Fever or signs of infection
• Breathing difficulties (in severe cases)

Diagnosis of Petechiae

Since petechiae can indicate a serious illness, a thorough examination by the vet is necessary. The diagnosis often includes the following steps:

Physical Examination

The vet examines the dog’s skin, mucous membranes, and eyes to determine the extent and distribution of the petechiae.

Blood Tests

• Complete blood count: Checking the number of platelets and other blood cells, looking for signs of infection or inflammation
• Coagulation profiles: Assessing the blood’s ability to clot, diagnosing coagulation disorders or poisoning

Specific Tests

• Depending on suspicion, specific tests for infectious diseases such as Ehrlichiosis, Anaplasmosis, or Leptospirosis
• Ultrasound or X-rays to search for tumours or organ changes

Bone Marrow Biopsy

If a bone marrow disease, such as leukaemia or other blood disorders, is suspected, a bone marrow examination may be performed.

Treatment of Petechiae

Treatment depends on the underlying cause, as petechiae are merely a symptom. Possible treatments:

Treatment of Thrombocytopenia

• In cases of immune-mediated thrombocytopenia, immunosuppressive medications such as corticosteroids are used to calm the immune system and increase platelet count
• In severe cases, a blood transfusion may be necessary

Coagulation Disorders

• If petechiae are caused by a coagulation disorder or poisoning (e.g., by rat poison), Vitamin K injections and, if necessary, blood transfusions are administered
• In genetic conditions such as von Willebrand disease, specific coagulation therapy may be required

Treatment of Infections

Bacterial or viral infections causing petechiae are treated with antibiotics, antivirals, or other appropriate medications.

Surgery or Chemotherapy

If a tumour is the cause of the petechiae, surgery, chemotherapy, or radiotherapy may be necessary.

Care and Support

In less severe cases, such as following trauma or with mild thrombocytopenia, the vet recommends rest, monitoring, and supportive measures.

Prognosis

The prognosis for petechiae depends heavily on the underlying condition. In many cases, a rapid diagnosis and appropriate treatment lead to full recovery, particularly if the cause is a transient illness or a poisoning-induced coagulation disorder. For conditions such as cancer or severe autoimmune or genetic disorders, the prognosis is individual and may require long-term treatment.