Causes of Petechiae in Dogs
What Exactly Are Petechiae in Dogs?
Petechiae in dogs are small, pinpoint-sized red or purple spots found on the dog's skin or mucous membranes. The term derives from the Italian word "petecchia" a term coined to depict a "mini bruise". These tiny red or purple spots are an indication of blood vessel leakage (i.e. bleeding under the skin). The white of the eyes, gums and skin (look inside the thigh or on the belly) are areas where the petechiae are often visible.
Petechiae are differentiated from other types of bleeding under the skin. Generally, petechiae are categorized as being less than 3 millimeters in diameter. Larger amounts of blood up to 1 centimeter are referred to as purpura, whereas spots larger than 1 centimeter are called ecchymoses. If light pressure is applied on these areas, they will typically not blanch (lose color) as they would do with a regular rash.
Dog owners are often aware of many life-threatening conditions such as bloat, choking and long-lasting seizures, but there may be also less-threatening looking conditions that may seem innocent, but require immediate veterinary attention.
Petechiae, purpura and ecchymoses all require immediate veterinary attention because they may indicate serious disorders that may quickly turn out being life-threatening.
Causes of Petechiae in Dogs
Petechiae may present alone and be the only symptom present, but if not investigated, it could soon lead to more symptoms that could cause life-threatening emergencies if the underlying causes aren't addressed.
It's not at all unusual for vets to see dogs spiral downhill within just 12 hours of the onset of the petechiae!
Recent trauma to a specific area may cause petichiae. Did your dog receive any blunt trauma to the area? While the occasional trauma may cause bleeding under the skin, the presence of petichiae without a history of any injury or trauma to the area should be immediately investigated as there may be serious conditions affecting the dog where every minute counts.
Platelets are responsible for stopping bleeding. When bleeding occurs, platelets stick together and form a temporary seal over the ruptured blood vessels. When the number of platelets are low, excessive bleeding occurs.
Thrombocytopenia takes place when the dog has a low amount of platelets, which are responsible for helping the blood to clot. This may trigger petechiae because of hemorrhages under the skin. Basically, the blood leaks through the walls of the dog's capillaries and ends up in the skin causing the red dots.
Thrombocytopenia is simply the term used to depict an abnormally low amount of platelets. The platelets may be low either because not enough are being made in the bone marrow, the platelets are being destroyed in the bloodstream or they are being destroyed in the spleen or liver.
Exposure to Rat Poison
Rat or mouse poison may contain potent anticoagulants that interfere with the blood's ability to clot. These products affect vitamin K metabolism causing life-threatening bleeding. Affected dogs may develop petichiae, ecchymoses, pale gums, lethargy, nosebleeds, blood in stools and urine.
Note: Your dog may not show other obvious symptoms right away other than signs of internal bleeding like the bruising and petechiae.
Sometimes, the immune system acts out and starts destroying the dog's platelets causing a condition known as immune-mediated thrombocytopenia. The reason for this remains unknown. In this case, they are destroyed in numbers up to 10 times greater than the normal platelet removal rate, explains veterinarian Wendy C. Brooks. In this case, spontaneous bleeding in the form of petechiae is the major clinical sign.
Does your dog live in an area populated with ticks? In this case, ticks are the culprit for causing tick-borne diseases known for causing petichiae and other significant symptoms that can't go ignored. Ehrlichiosis and Rocky Mountain Spotted fever are tick-borne diseases known for causing bleeding disorders.
Has your dog been for a while in the sun or is he prone to overheating? When heat stroke is allowed to progress, the dog may have dark brick red gums, develop seizures and may develop petechial hemorrhages in the gums or skin. Usually, by the time you notice the petichiae, you would have noticed something was seriously wrong with your dog.
Note: Always see your vet, even if your dog seems better after heat stroke, as disseminated intravascular coagulopathy may occur even several hours later.
There are several other potential causes of petichiae such as bone marrow cancers, infectious diseases, hereditary diseases such as von Willebrand's, reaction to drugs/vaccinations, vasculitis, shock, and disseminated intravascular coagulation.
Diagnosis and Treatment for Petichiae in Dogs
Your vet will likely look at your dog's gums to look for signs of anemia. He will likely request to have blood work done. A low platelet count is a sign of trouble. Normally, in a healthy dog, there are more than 600,000 platelets per microliter of blood, when platelet numbers fall to 10,000 to 40,000 per microliter that's when spontaneous bleeding may start to happen, according to Pet Place. Serum biochemistry will help determine if there is organ malfunction.
Other specific tests may be run to rule out tick-borne diseases. X-rays to check for infections and rule out cancer. Ultrasound may be taken to view organs. Immune system testing to determine if the immune system is attacking the dog's platelets. Urinalysis may detect the presence of blood in the urine.
Treatment is based on taking care of the underlying causes. Dogs with low platelet counts should be kept quiet and confined to minimize the bruising and bleeding. Their respiratory rate needs to be monitored. In a normal, resting dog, expect around 20 breaths per minute. In a dog with a clotting disorder, anemia could be double that, explains veterinarian Dr. Fiona. Severe cases will require blood transfusions.
If the dog's immune system is destroying platelets, steroids are needed in order to inhibit this destruction. Antibiotics, tetracyclines are needed to treat Rocky Mountain spotted fever and ehrlichiosis. In the case of cancer, chemotherapy drugs may be used.
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This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2014 Adrienne Janet Farricelli