What Causes Blood in Mucus, and How Do You Know If It’s an Emergency?

1. Airway irritation from coughing

Irritation in your airways from a severe or chronic cough is one of the most common reasons for blood in mucus. Coughing can irritate the walls of the airways in your lungs or throat. This irritation can result in blood streaks in the mucus.

2. Lung infection

A lung infection can lead to mild bleeding that causes blood in mucus. Your lungs have many blood vessels that absorb oxygen for your body. Sometimes, an infection can make these blood vessels break and bleed.

The lung infections that are most likely to cause blood-tinged mucus are:

• Bronchitis

• Pneumonia

• Tuberculosis

When an infection is causing blood in mucus, other symptoms are often present, such as:

• Fever

• Chest pain

• Productive cough (a cough that brings up mucus)

3. Bronchiectasis and COPD

Bronchiectasis occurs when infections or inflammation damage the small airways in your lungs over time. These damaged airways have a hard time clearing mucus, so it builds up. This can lead to chronic cough and frequent infections.

Bronchiectasis is common in people with chronic lung conditions, like cystic fibrosis or chronic obstructive pulmonary disease (COPD).

In addition to bloody mucus, symptoms of bronchiectasis may include:

• A daily, chronic cough

• Lots of brown mucus 

• Shortness of breath

• Chest pain

• Nail clubbing (nail changes leading to thick and curved nails)

4. Inflammation

Any condition that causes inflammation in your body and lungs can lead to bloody mucus. This is commonly seen when autoimmune conditions affecting your lungs, such as:

• Lupus

• Vasculitis

• Granulomatosis with polyangiitis (previously called wegener’s granulomatosis)

• Sarcoidosis

• Rheumatoid arthritis

If an autoimmune condition is the reason for bloody mucus, there are often other symptoms as well. These can include:

• Rash

• Hair loss

• Fatigue

• Achiness

• Swollen lymph nodes

5. Heart failure

Heart failure doesn’t just affect the health and function of your heart. It can also cause congestion and pressure to build up in your lungs. This buildup can cause small breaks in the blood vessels in your lungs. 

Although heart failure can lead to a cough with bloody mucus, other symptoms are usually more common. Classic symptoms of heart failure are:

• Shortness of breath (can be worse when lying down)

• Weight gain

• Body swelling (mostly in your legs, feet, and abdomen)

• Fatigue

• Lightheadedness

6. Pulmonary embolism

A pulmonary embolism (PE) is a blood clot in your lungs. It often starts as a blood clot in your leg that travels to your lungs. A PE doesn’t always lead to any bleeding in your lung, but it can.

Sometimes, a PE causes no symptoms. But when symptoms do happen, they can include: 

• Chest pain

• Shortness of breath

• Heart palpitations

• Dizziness or lightheadedness

• Pain or swelling in your legs

A pulmonary embolism is a serious condition that can also be deadly. If you have any of these symptoms, seek medical attention right away.

7. Cancer

Bleeding in your lungs can result from lung cancer or the spread of other cancers to your lungs. This bleeding can cause brown mucus or bloody phlegm.

Things that can increase your risk of lung cancer include:

• Smoking

• Chemical exposure

• Secondhand smoke exposure

• Family history of lung cancer

• History of radiation to your chest

People who have smoked are up to 30 times more likely to get lung cancer than those who have never smoked. If you’re coughing up blood and have a history of smoking, it’s a good idea to talk to your primary care provider. Screening for lung cancer is easier than other cancers.

8. Blood thinner medications

Anticoagulants (blood thinners) can increase the risk of bleeding in any part of your body. Blood thinners are more likely to cause bleeding from your nose or gastrointestinal tract. Bleeding in your lungs is less common. But it can happen, especially if a person taking blood thinners also has any of the lung conditions listed above. 

9. Injury to the lungs or arteries

Serious injuries to the chest area can lead to bleeding in your lungs. These types of injuries include:

• Pulmonary contusion (a large bruise on your lung)

• Lung laceration (a cut in the lung tissue)

These types of injuries typically only happen after more severe trauma, like a high-speed car crash. More minor injuries — like a broken rib from a fall — usually don’t cause blood in mucus. 

Can blood in mucus come from the throat or nose?

Sometimes, bloody mucus comes from bleeding in the upper part of your airway, like your nose or throat. These areas are filled with tiny blood vessels that can easily be irritated by inflammation or infection. 

If you’re coughing up blood or brown mucus, it might be from:

• Throat infection (pharyngitis)

• Tonsillitis

• Nasal congestion

• Nosebleeds

It can also be hard to tell where the blood is coming from. In some cases, bloody mucus could actually be coming from bleeding in your stomach or esophagus.

Should you see a healthcare professional for bloody mucus?

If you have repeated episodes of bloody mucus, it’s a good idea to get medical care. Some conditions that can cause blood in mucus can be serious. So, it’s important not to ignore this symptom. 

But this doesn’t mean you should worry. If you’re otherwise healthy, there’s a good chance the cause is nothing serious. 

The best way to find out what’s causing bloody mucus is to talk to a healthcare professional. They can check things out with some simple tests, like a chest X-ray or blood work. Getting checked is especially important if you have a history of: 

• Heart problems

• Autoimmune disease

• Lung conditions

• Cancer

• Heavy smoking

Is coughing up blood an emergency?

If you have small streaks of blood in your mucus but feel well otherwise, you can get checked out at a primary care provider’s office. For anything more than small streaks, it’s a good idea to see someone sooner rather than later.

Pay attention to how the mucus looks, how much blood you’re coughing up, and any other symptoms you’re having. Go to an ER if you’re experiencing any of the following:

• Episodes of coughing that produce more than 1 tsp of blood

• Chest pain

• Shortness of breath

• Abnormally pale skin

• Dizziness when standing

• Complete loss of appetite or unexplained weight loss

• Fever

• Severe weakness or fatigue

It’s best to go to an ER instead of urgent care if you have these symptoms. An ER has more testing and treatment available if needed. This is the fastest way to rule out serious conditions.

How is hemoptysis (bloody mucus) treated?

The main way to treat hemoptysis is to treat the underlying cause. This means treatment for bloody mucus will vary from person to person. 

In most cases, the bleeding itself doesn’t require any specific treatment. But people who take blood thinners may need to temporarily hold their medication until the bleeding stops.

If someone develops life-threatening bleeding in their lungs, treatment can involve:

• A breathing tube (also called intubation)

• A special procedure called embolization, which clots off the bleeding blood vessel

• Surgery, but only in severe cases

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Written by:

Michael Dreis, MD

Dr. Dreis is an emergency medicine physician currently practicing in Milwaukee, Wisconsin. He went to medical school at the University of Wisconsin – Madison and completed his residency at Henry Ford Hospital in Detroit, Michigan.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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