Blood in Phlegm: 14 Common Causes (& What to Do)

Blood in phlegm is usually the result of prolonged coughing or dried airway, particularly when it is noted in young, healthy people. People who take anticoagulants may also notice some specks of blood in their sputum. 

However, blood in phlegm with other symptoms, like shortness of breath, fever, and green, yellow or frothy phlegm may be a sign of a more serious health condition, like a respiratory infection, bronchitis or pulmonary edema. 

If you notice  copious amounts of blood in your phlegm, if it lasts for over 3 days, or if you experience other symptoms, like difficulty breathing or wheezing, you should see a doctor or lung specialist for assessment possible treatment. 

Imagem ilustrativa número 1

What causes blood in phlegm?

Bloody phlegm can occur for the following reasons: 

1. Persistent coughing

Allergies, the flu and persistent coughing can all cause blood in phlegm that is coughed up. This occurs due to irritation in the respiratory airways, which can become cracked and lead to some blood mixed with phlegm. These conditions are usually temporary and not serious, and the blood resolves within a few days, when the coughing improves. Read more about what can cause a persistent cough and how to treat it. 

What to do: You should try to soothe your coughing to avoid any further irritation. Some options include maintain hydration throughout the day, performing nasal irrigation to hydrate the mucous membranes, and taking a homemade cough syrup like propolis. Antihistamine medications, like loratadine, can also help.

You can also check-out these home remedies for coughs as a complement to your prescribed treatment.  

2. Dried airways

Dried airways can affect the nose, larynx and pharynx and cause coughing up phlegm with blood. This dryness can be a result of a cold, flu or allergy, or as a result of persistent coughing or sneezing. It leads to irritation of the mucosa that lines the airways, leading to micro wounds and scant bleeding.

It is also possible that the airways can dry up as a result of a dry environment or temperatures. Dry rooms or climates and cause ruptures to the tiny vessels within the nose and throat, leading to phlegm with blood. 

What to do: In these cases, it is important to drink plenty of fluids and to perform nasal irrigation to keep the airways hydrated. Anti-inflammatory medications can also help to relieve related symptoms. 

3. Anticoagulant medications

People who use anticoagulants, like warfarin or heparin, are at a higher risk for bleeding in various parts of the body. These medications make the blood thinner, which can put the patient at a higher risk for bleeding in various areas of the body. Anticoagulants can cause irritation to the respiratory tract, and a mild allergy, for example, can cause scant amounts of bleeding when coughing up phlegm.

What to do: Small amounts of blood in phlegm are not a significant finding, however large amounts of blood should. be assessed by a doctor.

4. Respiratory infections

Another relatively common cause of blood in phlegm is a lung infection, which can range from a mild cold or flu infection, to a more serious condition like pneumonia or tuberculosis. 

Respiratory infections are usually associated with other symptoms, like yellow or green phlegm, difficulty breathing, pale skin, blue lips or fingers, fever and chest pain. 

What to do: If you suspect a respiratory infection, you should see a doctor to confirm a diagnosis. After identifying the infectious agent, the doctor can initiate treatment, which may involve antibiotic use. See other ways you can get rid of phlegm using natural remedies as complement to medical treatment. 

5. Use of nasal decongestants

Using nasal decongestants regularly or for several days can cause bloody phlegm, as these medications may cause irritation and dryness of the nasal mucosa. This makes the tissue in the airways more prone to bleeding.

What to do: It is important to use nasal decongestants only as prescribed for a doctor, and to use them during the recommended time. Instead of nasal decongestants, you can use saline solution three times per day to irrigate the nose throughout the day.

6. Allergic rhinitis

Allergic rhinitis is a condition that involves hyper-sensitivity of the mucous membrane of the nose. This lining becomes inflamed when it comes into contact with certain substances, such as dust, pollen or animal hair.

These substances trigger an allergic reaction, resulting in symptoms such as sneezing, a runny nose, bloody phlegm and an itchy nose.

What to do: it is important to avoid contact with allergy triggers if possible. The doctor may recommend the use of allergy medications, such as desloratadine or cetirizine, to manage more severe symptoms. Read more about the allergic rhinitis medications your doctor may prescribe.

You can also prepare natural treatments at home to manage symptoms, such as inhaling eucalyptus steam or drinking peppermint tea. 

7. Dry weather or changes in atmospheric pressure

Dry, low-humidity weather, which is common in winter, or changes in atmospheric pressure that can occur when flying, climbing to high altitudes, or diving can cause also cause blood in the phlegm or nosebleeds.

This is because, in dry weather, the nasal mucus dries out, causing crusts or crack. This increases the likelihood of bleeding when the nose is rubbed, picked or blown.

In cases of atmospheric pressure changes, bleeding occurs due to irritation of the mucous lining of the nasal sinuses as a result of the intrasinusal pressures not matching the ambient pressure.

What to do: For dry weather, it is important to open the windows to keep the house airy or use a humidifier. Additionally, you should avoid activites that involves changes in pressure, like diving or hiking to high altitudes, if you have an upper respiratory infection or active allergic rhinitis.

Frequent nosebleeds can be treated prophylactically with medications prescribed by your doctor, such as oxymetazoline sprays, pseudoephedrine and topical intranasal glucocorticoids.

8. Sinusitis

Sinusitis is the inflammation of the lining of the paranasal sinuses and cavities in the face. This swelling is caused by bacteria, viruses, fungi or allergies, and can cause symptoms such as nasal congestion, facial pain, runny nose and headache. See other symptoms of sinusitis.

Blood in the phlegm can also occur due to swelling and increased sensitivity of the mucous membranes that line the sinuses. 

Also recommended: Chronic Sinusitis: Symptoms, Diagnosis, Causes & Treatment

What to do: To relieve sinusitis symptoms, you can wash your nose with saline solution at least 3 times a day, and avoid being in closed spaces. Inhaling the steam during a shower can also be beneficial. Furthermore, the general practitioner or otorhinolaryngologist may recommend sinusitis medications, which can vary depending on the underlying cause of the sinusitis.

Check-out some natural ways to treat sinusitis at home using our simple tips.

9. Use of inhaled drugs or other irritants

The use of inhaled illicit drugs, such as cocaine or poppers, for example, or constant exposure to cleaning products or other chemical vapors can also lead to blood in the phlegm and nose bleeds.

Also recommended: Nose Bleeds: 8 Common Causes & What to Do

This occurs because inhaling these substances irritates the nasal lining, causing the blood vessels to contract and the mucosa to dry out. Touching the nose or blowing it can lead to easy rupture of the blood vessels, causing nose bleeds. 

What to do: It is important to stop using drugs, and to move away from any environments with chemicals in the air that can be inhaled. You should avoid blowing your nose or handling it forcefully, as this can worsen bleeding.

If you experience a nose bleed, tilt your head forward and apply pressure to the soft tissue of your nose with your fingers for 10 to 15 minutes. If the bleeding does not stop after this time, go to the nearest emergency room.

10. Post nasal surgery

During the postoperative period of nasal surgery, bloody phlegm can occur due to several factors, such as irritation of the nasal mucosa and paranasal sinuses from surgical interventions or swelling. This can cause nasal congestion and hinder normal mucus drainage, contributing for the presence of blood in the phlegm.

Additionally, the presence of clots, which can form during healing, when mixed with phlegm, makes the phlegm appear bloody.

What to do: It's important to follow post-surgical care as instructed by your surgeon. He or she may prescribe nasal sprays or other medications to reduce swelling, and may show you the proper way to clean your nose, which usually is with saline solutions.

In addition, it is important to avoid blowing forcefully or handling your nose roughly, avoiding lifting weights or blowing forcefully, and trying to keep your head elevated by using pillows or tilting your torso slightly upwards, to help reduce nasal congestion and the bleeding. It is also important to drink plenty of water to keep the mucous membranes hydrated and prevent nasal dryness.

11. Bronchiectasis 

Bronchiectasis is a chronic condition that is associated with permanent dilation of the bronchi. This can lead to excessive phlegm production, as well as frequent shortness of breath. The presence of blood in the phlegm is also a common finding. 

This condition does not have a cure, however treatment prescribed by a lung specialist can help relieve symptoms during flare-ups. 

What to do: Bronchiectasis should always be diagnosed by a doctor so that appropriate treatment can be prescribed. If you suspect you may have this condition, see a lung specialist for further examination with a chest x-ray and a thorough lung auscultation. 

12. Bronchitis

Bronchitis can also be associated with blood in phlegm. This condition is characterized by recurrent bronchial inflammation, which increases airway irritation and risk for bleeding. 

Phlegm from bronchitis is usually white or slightly yellow, although some strings of blood can also be noted. Other symptoms include wheezing, frequent fatigue and shortness of breath. 

What to do: Many times, rest and adequate hydration are sufficient for relieving bronchitis symptoms, However, if symptoms persist or if breathing worsens, you should seek medical assessment, as you may need IV medication. People who have chronic bronchitis are usually followed by a lung specialist, who will typically prescribe bronchitis medication to manage symptom flare-ups. 

Also recommended: 10 Home Remedies for Bronchitis (Natural Recipes to Try)

13. Pulmonary edema 

Pulmonary edema occurs when fluid accumulates inside the lungs. It is common in people with heart problems, like congestive heart failure, in which the blood is not adequately pumped to the rest of the body and starts to accumulate in small blood vessels in the lungs. 

In these cases, phlegm is often red or pink in color, and looks likely foamy. Other symptoms of pulmonary edema include difficulty breathing, blue lips or fingers, chest pain and increased heart rate. 

What to do: Pulmonary edema is considered a medical emergency. If you have a history of cardiac disease and suspect changes to your lung functioning, you should proceed immediately to the emergency room to confirm a diagnosis and start prompt treatment. Many times, hospital admission for treatment is advised. 

14. Lung cancer

Lung cancer is a more rare condition, but it can cause phlegm with blood. This type of cancer is most commonly seen in people over the age of 40 and in people who smoke. 

Other symptoms of lung cancer include persistent coughing that does not improve, weight loss, hoarseness, back pain and extreme fatigue. 

What to do: If you suspect cancer, especially if you have risk factors for cancer, you should see a lung specialist to complete thorough testing and confirm a diagnosis. Generally, the earlier cancer if caught, the better the rate of cure. 

When to see the doctor

You should consult your family doctor or a lung specialist if you persistently notice blood in phlegm. 

Urgent medical attention is advised if you experience any of the following: 

  • Blood in phlegm that does not improve after 3 days 
  • Large amounts of blood in the phlegm
  • Other symptoms, like high-grade fever, extreme difficulty breathing, pale skin, or blue fingers or lips

In the presence of these symptoms, the doctor may order testing like a chest x-ray, spirometry or a CT scan.