Is Coughing Up Blood a Sign of Cancer?

This page is for anyone who has coughed up blood and wants to know how urgent it is. It covers when to get help, the common causes, and where lung cancer fits in.

The amount of blood decides how fast you need help, and the other symptoms that come with it matter too.

MedlinePlus, the US National Library of Medicine's health site, says to get medical help right away for a cough that produces more than a few teaspoons of blood. The same advice applies when the blood comes with chest pain, fever, dizziness, lightheadedness, severe shortness of breath, or blood in the urine or stools.

CDC adds the signs of a clot in the lung, which it says need immediate medical attention: difficulty breathing, chest pain that often worsens with a deep breath or cough, coughing up blood, and a faster than normal or irregular heartbeat.

For small amounts, MedlinePlus still says do not sit on it. Contact a provider any time you cough up blood, even if you have no other symptoms.

• Call 911 now: more than a small amount of blood. MedlinePlus puts its line at more than a few teaspoons.
• Call 911 now: any blood plus trouble breathing, chest pain, a fast or irregular heartbeat, dizziness, lightheadedness or fever.
• Call your doctor or care team today: a few small flecks or streaks, even once, even feeling well.
• Call your doctor or care team today: small amounts that keep coming back over days.

If you need emergency care, do not drive yourself. Call 911 so help comes to you.

Hemoptysis (hee-MOP-tih-sis) is the medical word for coughing blood up from the respiratory tract. MedlinePlus is careful to separate it from two other things it gets confused with: bleeding from the mouth or throat, and bleeding from the gut.

The look gives a clue. Blood from the lungs is often bubbly, because it comes up mixed with air and mucus. It is usually bright red, though it can be rust-colored. Sometimes the mucus only carries streaks.

MedlinePlus is also honest about outcome. Most people do well once the underlying problem is treated. Severe bleeding from the lungs can be life-threatening. That is the reason the amount drives the response.

The MedlinePlus cause list is long, and cancer is one line on it.

Infection is well represented: pneumonia and other lung infections, bronchitis, tuberculosis. So are structural problems, such as bronchiectasis, where the airways are permanently widened. Cystic fibrosis appears. So does a blood clot in the lung.

Several causes have nothing to do with lung disease itself. Very thin blood from blood-thinning medicine is listed, most often at higher than recommended levels. So is breathing food or other material into the lungs. So is violent coughing, which can irritate the throat enough to produce small amounts of blood. Other causes on the list include:

• inflammation of lung blood vessels
• lupus
• pulmonary edema (fluid in the lungs)
• injury to lung arteries

Bronchoscopy with biopsy can cause it too.

Lung cancer is named directly on the MedlinePlus list. The American Cancer Society lists coughing up blood or rust-colored phlegm among the most common symptoms of lung cancer, alongside a cough that does not go away or gets worse, chest pain, hoarseness, weight loss and shortness of breath.

NCI's framing is worth holding alongside that. It says cancer can cause many symptoms, but those symptoms are most often caused by illness, injury, benign tumors or other problems. Its own list includes a cough or hoarseness that does not go away.

So coughing up blood is a reason to be checked, not a diagnosis. It is on the short list of lung cancer symptoms, and it is also caused by many conditions that are not cancer. What clinicians weigh is the pattern around it: how much, how often, how long, and what else changed.

MedlinePlus sorts cough by how long it lasts. Acute coughs usually go away after 3 weeks. Subacute coughs last 3 to 8 weeks. Chronic coughs last longer than 8 weeks.

The usual causes are everyday ones. MedlinePlus lists colds, flu and other viral infections, lung infections, allergies, sinus drainage down the back of the throat, asthma, COPD and acid reflux as common causes. Lung cancer is on its list of other causes.

Blood sits outside that scheme. MedlinePlus says to contact a provider right away for a cough that produces blood, however long the cough has lasted. The duration rules stop applying.

MedlinePlus lists tests that may follow the exam:

• a chest x-ray or a chest CT scan
• a complete blood count
• clotting tests such as PT/INR or PTT
• sputum culture and smear (lab tests on the mucus you cough up)
• bronchoscopy, to look inside the airways directly
• a lung scan, a lung biopsy, or pulmonary arteriography (an x-ray of the lung arteries)

The questions come first, though, and they are specific: how much blood, how many times, how long, worse at night, and whether any blood-thinning medicine is being taken.

MedlinePlus also flags a trap in home care. Cough suppressants can help when the bleeding comes from violent coughing. But they can block the airway, so a clinician should be asked before one is used.

The details that change the answer are easy to lose in the moment.

Write down the amount, in teaspoons if possible. Note whether it was mixed with mucus or came alone. Count the episodes. Note the start date. List every medicine, especially anticoagulants (blood thinners). Add recent infections, recent injuries, smoking history and any personal history of cancer. Say whether it is improving or getting worse.

For wider context, see symptoms of cancer, is a persistent cough a sign of cancer, and is blood in sputum a sign of cancer.

• MedlinePlus — Coughing up blood
• MedlinePlus — Cough
• CDC — Blood clots and cancer
• American Cancer Society — Signs and symptoms of lung cancer
• NCI — Symptoms of Cancer