Can a pulmonary embolism cause coughing up blood? 

A pulmonary embolism is a serious medical condition that occurs when a blood vessel in your lung becomes blocked, usually by a blood clot. While many people are aware of symptoms like chest pain or breathlessness, coughing up blood is another significant sign that can occur. Understanding why this happens and how to identify it alongside other symptoms is essential for ensuring prompt medical evaluation according to UK health standards. 

What We’ll Discuss in This Article 

• Whether coughing up blood is a common sign of pulmonary embolism. 

• The medical term for this symptom and why it occurs in the lungs. 

• How to distinguish between different types of blood in a cough. 

• Other primary symptoms that often appear with a lung clot. 

• Associated risk factors such as deep vein thrombosis (DVT). 

• When to seek immediate emergency medical care in the UK. 

Coughing up blood is a recognised symptom of a pulmonary embolism 

Coughing up blood, known medically as haemoptysis, can indeed be caused by a pulmonary embolism. While it is not present in every case, it often occurs when the blood clot causes damage to the lung tissue or the lining of the airways due to a lack of oxygenated blood flow. This symptom is considered a significant clinical indicator that requires urgent investigation to determine the underlying cause and extent of the blockage. 

The NHS lists coughing up blood as one of the key symptoms of a pulmonary embolism that requires immediate medical attention. It usually appears alongside other respiratory distress, such as sudden shortness of breath or sharp chest pain. Even if the amount of blood is small, its presence in a cough following a sudden onset of breathing difficulties is a priority for healthcare professionals during an assessment. 

How blood appears when caused by a lung clot 

When a person with a pulmonary embolism coughs up blood, the appearance can vary depending on the severity of the lung involvement. It may appear as bright red streaks in the mucus or phlegm, or in more severe cases, it can manifest as larger amounts of frothy, blood-stained fluid. This happens because the pressure in the lung’s blood vessels increases behind the blockage, leading to small amounts of leakage into the air sacs. 

It is important to note that this is different from blood that might come from a nosebleed or a cut in the mouth. Blood originating from the lungs is typically mixed with phlegm and may appear bubbly because it has been mixed with air. NICE clinical guidelines state that haemoptysis is a specific sign used to calculate the clinical probability of a pulmonary embolism in emergency settings. 

Other symptoms that frequently accompany coughing up blood 

Coughing up blood is rarely an isolated symptom during a pulmonary embolism and is almost always accompanied by other signs of respiratory or circulatory strain. The most common accompanying symptom is sudden or worsening shortness of breath, which may feel like you cannot get enough air even while resting. Sharp chest pain that feels worse when taking a deep breath is also frequently reported. 

A rapid heart rate and feeling lightheaded or dizzy are also common. These signs indicate that the heart is working harder to pump blood through the obstructed vessels in the lungs. Because the body is struggling to maintain oxygen levels, a person may also appear pale or have a slightly bluish tint to their lips or fingernails, a condition known as cyanosis. 

Comparing pulmonary embolism with other causes of coughing up blood 

There are several reasons why a person might cough up blood, and medical professionals must distinguish between them to provide the correct treatment. While a pulmonary embolism is a critical cause, other conditions like severe chest infections or long-term lung issues can also present similarly. 

Condition	Nature of Coughing Up Blood	Common Accompanying Signs
Pulmonary Embolism	Sudden onset, often bright red streaks.	Sudden breathlessness, sharp chest pain.
Pneumonia	Blood-stained or “rusty” phlegm.	High fever, shivering, and deep cough.
Acute Bronchitis	Small amounts of blood after heavy coughing.	Sore throat, wheezing, and chest congestion.
Tuberculosis	Persistent coughing up of blood over weeks.	Weight loss, night sweats, and fatigue.

The relationship between leg clots and lung symptoms 

A pulmonary embolism often starts as a blood clot in the deep veins of the leg, known as deep vein thrombosis (DVT). If a person experiences coughing up blood alongside swelling or pain in one leg, the clinical suspicion of an embolism is very high. The clot in the leg can break off and travel through the bloodstream to the lungs, where it causes the blockage and subsequent symptoms. 

Healthcare providers will often check for signs of DVT, such as warmth and redness in the calf, when a patient presents with unexplained respiratory symptoms. Identifying this link is a vital part of the diagnostic process in the UK. If you have recently had surgery, been on a long flight, or remained immobile for a long period, you are at a higher risk of developing these types of clots. 

Conclusion 

Coughing up blood is a serious and recognised symptom of a pulmonary embolism, often indicating that the lung tissue is under significant strain from a blood clot. It typically occurs alongside sudden shortness of breath and sharp chest pain that worsens with breathing. Recognising these signs together is crucial for ensuring that this life-threatening condition is treated as an emergency. 

If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was created to provide the public with clear, evidence-based information on the symptoms of pulmonary embolism, specifically focusing on the occurrence of coughing up blood. It has been reviewed by Dr. Stefan Petrov, a UK-trained physician with extensive experience in emergency medicine and general practice. The content adheres strictly to the clinical guidelines provided by the NHS and NICE to ensure accuracy and patient safety.