Phlegm is a thick, sticky substance produced by the mucous membranes lining the respiratory tract, including the lungs and airways. Its primary role involves trapping irritants, pathogens, and foreign particles, which are then expelled from the body, often through coughing. While seeing blood in phlegm, medically termed hemoptysis, can be unsettling, it does not always indicate a severe health problem. Knowing what blood in phlegm looks like and when to seek medical advice is important.
How Blood in Phlegm Appears
The appearance of blood in phlegm can vary significantly in color, form, and amount. Fresh bleeding often presents as bright red streaks or specks within the phlegm. It may also appear frothy or bubbly due to mixing with air, indicating recent bleeding from the respiratory passages.
Older blood can look different, appearing as pinkish, rust-colored, or even dark brown specks or stains. A pinkish tinge may suggest a small amount of blood mixed with mucus. Dark brown or black phlegm indicates older blood that has oxidized, or it may be associated with chronic inflammation.
The form can range from thin streaks or flecks to larger clots or a uniform mixture throughout the phlegm. The quantity varies from barely noticeable specks or a slight tinge to larger amounts. It is helpful to distinguish blood from the lungs from blood originating in the digestive tract, which typically appears dark, like coffee grounds, and may be accompanied by food particles. Blood from a nosebleed can also drain into the throat and be coughed up, mimicking hemoptysis.
Potential Reasons for Blood in Phlegm
Blood in phlegm can arise from various causes, ranging from minor irritations to more serious underlying conditions. One common reason is forceful or prolonged coughing, which can irritate the delicate lining of the airways and rupture small blood vessels. This often occurs during severe colds, flu, or bouts of bronchitis, where inflammation contributes to bleeding. Minor throat irritation or dry airways can also lead to small amounts of blood in phlegm. People taking anticoagulant medications, which thin the blood, may also notice occasional blood streaks.
More significant causes include lung infections such as pneumonia or tuberculosis, which can damage lung tissue and blood vessels. Chronic lung conditions like bronchiectasis (widened airways) or cystic fibrosis (thick mucus buildup) can also lead to recurrent bleeding. Blood clotting disorders or certain heart conditions, such as pulmonary edema, may also result in bloody phlegm. Blood in phlegm can also be a symptom of lung cancer or a pulmonary embolism (a blood clot in the lungs).
When to Consult a Doctor
Seeking medical attention for blood in phlegm is advisable, even if the amount is small. An immediate medical evaluation is necessary if you are coughing up large amounts of blood (more than a few teaspoons) or if the bleeding is persistent and worsening. Accompanying symptoms that warrant urgent care include difficulty breathing, chest pain, dizziness, lightheadedness, or a rapid heart rate. Foamy, pink-tinged sputum, unexplained weight loss, or night sweats also require immediate medical assessment.
Even small amounts of blood in phlegm should prompt a visit to a doctor if it occurs repeatedly or if you have pre-existing lung conditions. Other concerning symptoms include persistent fever, a lingering cough, or changes in the color or consistency of your phlegm, such as it becoming yellow or green. A doctor will inquire about the amount, color, and frequency of the blood, along with any other symptoms, to help determine the underlying cause.