A dog coughing up blood-tinged mucus can be alarming and distressing. While some coughing might be minor, the presence of blood indicates irritation or damage to the airways or lungs, which can be serious if left untreated.
We outline the common reasons why a dog may cough up bloody mucus in dogs, what you can do and why urgent veterinary care is necessary.
Dog Coughing Bloody Mucus: Why It Happens
Coughing up bloody mucus in dogs occurs when the airways or lungs are inflamed, irritated, or injured. The blood may come from ruptured capillaries in the trachea, bronchi, or lungs, and is often mixed with mucus produced during coughing.
Common causes include respiratory infections, heart disease, trauma, or chronic airway conditions.
Dog Coughing Bloody Mucus: Common Causes
Respiratory Infections
Respiratory infections, including kennel cough, canine influenza, and bacterial pneumonia, can inflame the airways and cause bloody mucus.
The infection leads to persistent coughing as the body attempts to clear the lungs and trachea of mucus and pathogens.
Dogs may also show fever, nasal discharge, lethargy, and reduced appetite. In severe cases, untreated infections can progress to pneumonia or sepsis, making prompt veterinary diagnosis and treatment essential.
Read more: Dog Coughing up white foamy mucus (Here’s why)
Heart Disease
Heart conditions such as congestive heart failure can cause fluid to accumulate in the lungs, leading to coughing with blood-tinged mucus.
The elevated pressure in the pulmonary vessels can rupture small capillaries, resulting in visible blood in the mucus.
Other signs may include rapid or labored breathing, exercise intolerance, fainting, or swelling in the limbs or abdomen.
Early detection is critical, as heart disease can progress quickly and may require medications to reduce fluid buildup and support cardiac function.
Collapsed Trachea
A collapsed trachea occurs when the cartilage rings supporting the windpipe weaken, narrowing the airway and making it prone to irritation. Persistent coughing can damage the tracheal lining, leading to mucus streaked with blood.
Small and toy breeds are particularly susceptible. You may notice a honking or hacking cough that worsens with excitement, activity, or eating.
If untreated, chronic irritation can result in long-term airway damage, making veterinary intervention necessary for both diagnosis and management.
Pulmonary Trauma or Injury
Injury to the chest, lungs, or airways can lead to bleeding within the respiratory system. Trauma may occur from accidents, rough play, or inhalation of sharp objects.
Symptoms often include coughing with blood, difficulty breathing, lethargy, and sometimes visible bruising or swelling on the chest.
Pulmonary trauma is serious because it can cause internal bleeding and compromise oxygen delivery, requiring immediate veterinary care.
Lung or Airway Tumors
Tumors in the lungs or airways can erode blood vessels, leading to coughing up blood-streaked mucus. These tumors may be benign or malignant, but either can obstruct airflow and irritate the respiratory tract.
Other indicators include weight loss, decreased appetite, fatigue, labored breathing, or persistent coughing that does not respond to typical treatments.
Early veterinary evaluation is essential for diagnosis, imaging, and developing an appropriate treatment plan.
Blood Clot or Pulmonary Embolism
Although less common, a blood clot or embolism in the lungs can cause coughing with bloody mucus. The clot can damage lung tissue and disrupt normal circulation, triggering respiratory distress and visible blood.
Dogs may also display sudden difficulty breathing, anxiety, pale or blue gums, and collapse in severe cases.
Pulmonary embolisms are life-threatening emergencies requiring immediate veterinary attention and intervention.
Read more: Dog Coughing with No Other Symptoms (Why it Happens and What to Do)
What to Do If Your Dog Is Coughing Bloody Mucus
If your dog coughs up blood-streaked mucus, it’s important to remain calm and observe their behavior carefully. Keep your dog in a calm, stress-free environment and prevent excessive activity, which can worsen coughing and airway irritation.
Monitor appetite, water intake, and energy levels, and keep a log of coughing frequency, mucus color, and any triggers.
Providing fresh water can help soothe the throat and thin mucus, but avoid giving any medications without veterinary guidance.
If the coughing appears mild and infrequent, contact your veterinarian for advice on monitoring and possible tests.
Do not attempt home remedies for severe or persistent coughing, as underlying causes can be life-threatening.
When to Call or Visit Your Vet
Seek immediate veterinary care if your dog shows any of the following:
- Persistent or worsening coughing with blood or mucus.
- Labored, rapid, or noisy breathing, or blue/pale gums.
- Signs of lethargy, weakness, collapse, or fainting.
- Coughing accompanied by fever, loss of appetite, or vomiting.
- History of heart disease, trauma, or chronic respiratory issues.
Even if symptoms seem mild, coughing up blood should always be evaluated, as early detection of serious conditions can significantly improve outcomes.
Read more: Dog Coughing After Barking (Causes and Solutions)
Key Takeaway
Coughing up bloody mucus in dogs is a concerning symptom that can result from infections, heart disease, airway collapse, trauma, tumors, or pulmonary embolisms. Occasional coughing may be minor, but blood in the mucus is always a red flag that requires veterinary evaluation.
At-home care involves keeping your dog calm, monitoring symptoms, and avoiding stress or excessive activity.
Immediate veterinary assessment is crucial for proper diagnosis, treatment, and ensuring your dog’s comfort and safety. Early attention can prevent complications and improve your dog’s quality of life.