Why COVID-19 May Cause Some People To Cough Up Blood

Many know the key symptoms of COVID-19 by heart (cough, fever, fatigue) as well as some of the more serious or unexpected symptoms (shortness of breath, diarrhea). However, according to research, a small percentage of COVID-19 cases have also reported the symptom of coughing up blood, and research has found evidence of reports of people coughing up blood with COVID-19.

Here's what to know about the rare occurrence—and why healthcare providers say it may not always be indicative of serious disease (though it should be brought to the attention of your healthcare provider).

What Exactly Does It Mean To Cough Up Blood—And How Worrisome Is It?

Coughing up blood (aka hemoptysis) is the spitting up of blood or bloody mucus from the lungs and throat. It should be noted that blood that comes up with a cough often looks bubbly since it's mixed with air and mucus. Per MedlinePlus, the blood can appear bright red or rust-colored and may only show up as streaks in mucus.

Hemoptysis may occur in a variety of diseases, according to Gregory Cosgrove, MD, vice president of clinical development for Pliant Therapeutics. But it's important to note that it's not always indicative of serious disease: "The amount/rate of blood expectorated and the presence of associated symptoms such as breathlessness, low oxygenation (hypoxia), or even changes in blood pressure," Dr. Cosgrove explained, all factor into the seriousness of coughing up blood.

According to MedlinePlus, a number of conditions, diseases, and even medical tests and medications can make a person cough up blood. A few include bronchitis, lung cancer, pneumonia, irritation of the throat from violent coughing, tuberculosis, a bronchoscopy, or even blood-thinning drugs.

Hemoptysis in general is never a symptom you should ignore (always call your healthcare provider, even if you cough up blood with no other symptoms), but "typically, patients cough up small flecks of blood intermixed with phlegm," Dr. Cosgrove said. At that point, your healthcare provider may tell you to manage symptoms (i.e., taking cough suppressants) to help minimize heavy coughing but to keep track of how long you cough up blood and how much blood is mixed with mucus.

In some cases, though, coughing up blood is an emergency: If you're coughing up more than a few teaspoons of blood, and if hemoptysis is accompanied by chest pain, dizziness, fever, lightheadedness, severe shortness of breath, and blood in your urine or stool, it's important you seek medical attention right away. Essentially, according to Dr. Cosgrove, "a simple rule would be that, should anyone cough up blood and have an acute, progressive change in symptoms, they should seek medical care regardless of the amount of blood coughed up."

How Common Is It To Cough Up Blood if You Have COVID-19?

It should be noted that hemoptysis has only been reported in a small number of COVID-19 patients. Researchers found that the overall worldwide prevalence of hemoptysis among COVID-19 symptoms was 3.3%.

Even though it may show up among the initial symptoms of the infection, hemoptysis is not necessarily a main diagnostic symptom of COVID-19. "Typically, COVID-19 infections cause cough, sputum production, and shortness of breath," Charles S. Dela Cruz, MD, a Yale Medicine pulmonologist and associate professor of medicine and microbial pathogenesis, told Health. "Hemoptysis, which is coughing up blood, is much less common in COVID-19."

However, hemoptysis has appeared in patients who previously had COVID-19. For example, researchers detailed the case of an individual who went to an intensive care unit with a moderate case of hemoptysis. The person was essentially healthy other than having had COVID-19 two months before the hemoptysis. Therefore, it may be that coughing up blood may be more of a secondary symptom—or a complication of symptoms or conditions most commonly caused by COVID-19.

What To Consider Concerning COVID-19 and Coughing Up Blood

Dr. Cosgrove explained that the severity of lung damage from viral pneumonia is likely the reason why some patients are coughing up blood. Dr. Dela Cruz agreed: "If it does happen, it can mean more severe COVID-19 infection or a patient has superimposed bacterial infections." Again, any type of viral or bacterial pneumonia can cause hemoptysis—not only pneumonia caused by COVID-19.

Of course, coughing up blood at any time can be alarming to both a patient and their family, but it should not be ignored in COVID-19 patients. "In the current environment, it should raise concern and be appropriately evaluated, especially if the hemoptysis is associated with shortness of breath," Dr. Dela Cruz said.

If you or a family member have tested positive for or have a suspected case of COVID-19 and begin coughing up blood, it's best to call your healthcare provider right away. As medical professionals, they can evaluate your symptoms further and determine any additional treatment, or suggest you come in for an in-person visit, if they believe it's necessary.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.