Coughing up blood (hemoptysis) can have many possible causes, some of which are serious, and some which may be of little concern. Blood that is coughed up often appears bright red and the sputum may look bubbly.
13 Coughing Up Blood Emergency Signs & Symptoms
It is important to see a doctor for a proper diagnosis to rule out serious conditions that can cause coughing up blood. See a doctor right away or go to a hospital’s ER if coughing up blood is due to trauma or injury to the chest or is accompanied by any of the following:
- Shortness of breath
- Signs of significant blood loss
- Weakness
- Dizziness on standing
- Lightheadedness
- Thirst
- Sweating
- Fast heartbeat
- Large amounts of blood coughed up (more than a one teaspoon)
- Unexplained coughing up blood
- Fatigue
- Blood is also in the urine or stool
- Having a tracheostomy
- If you also take blood thinners (anticoagulants)
What Causes Coughing Up Blood?
Causes of coughing up blood include:
- Respiratory tract infection (most common cause)
- Chronic obstructive pulmonary disease (COPD)
- Smoking
- Inhaled (aspirated) foreign object that (usually seen in children)
- Cystic fibrosis
- Certain types of cancer
- Fungal infection with Aspergillus (aspergillosis)
- Tuberculosis
- Pulmonary edema
- Wegener's granulomatosis
- Inflammation of blood vessels (vasculitis) in the lung
- Goodpasture syndrome
- Granulomatosis with polyangiitis
- Certain drugs or chemicals
- Certain medical procedures
- Tonsillectomy
- Bronchoscopy
- Laryngoscopy
- Spirometry
- Upper airway biopsy
Uncommon causes of coughing up blood that can be serious or life-threatening include:
- Acute bronchitis
- Other lung infections such as bacterial lung abscess and/or necrotizing pneumonia
- Immunologic lung diseases, such as anti-glomerular basement membrane (anti-GBM; Goodpasture) disease, granulomatosis with polyangiitis, systemic lupus erythematosus (SLE), idiopathic pulmonary hemosiderosis, primary antiphospholipid antibody syndrome, Behçet syndrome, and microscopic polyangiitis
- Penetrating, rather than blunt, trauma
- Pulmonary vascular diseases
- Pulmonary arteriovenous malformations (PAVMs)
- Mitral stenosis
- Blood clot in the lung (pulmonary embolism)
- Congenital heart disease or severe pulmonary hypertension
- Chemotherapy and bone marrow transplantation
- Acquired and iatrogenic trauma
- Posterior arterial nosebleeds
- Heart failure and heart valve disorders
- Right heart catheterization (i.e., pulmonary artery catheterization)
- Fistulas, such as fistulas between the aorta and the airway
- Medical interventions, including percutaneous or transbronchial lung biopsy, cryobiopsy, central vein venipuncture during pacemaker insertion, and ablative procedures for endobronchial masses
How Is Coughing Up Blood Diagnosed?
In addition to a patient history and physical examination, the cause of coughing up blood is diagnosed with tests such as:
- Chest X-ray
- Chest computerized tomography (CT) scan
- Blood tests
- Complete blood count (CBC)
- Blood chemistry
- Arterial blood gas
- Urinalysis
- Coagulation studies such as prothrombin time (PT) or partial thromboplastin time (PTT)
- Bronchoscopy
- Lung biopsy
- Lung scan
- Pulmonary arteriography
- Sputum culture and smear
- Pulse oximetry
What Is the Treatment for Coughing Up Blood?
In mild cases, coughing up blood may go away on its own or when the underlying cause is treated.
Smokers should stop smoking. Other treatments for coughing up blood may include:
- Antibiotics for pneumonia, tuberculosis, or other bacterial infections
- Chemotherapy or radiation for lung cancer
- Steroids for inflammatory conditions
Treatment for serious cases of coughing up large amounts of blood may require hospitalization which may include a stay in the hospital’s intensive care unit (ICU).
From 
Lung Disease/COPD Resources
https://www.merckmanuals.com/home/lung-and-airway-disorders/symptoms-of-lung-disorders/coughing-up-blood
https://www.uptodate.com/contents/etiology-of-hemoptysis-in-adults?search=Coughing%20Up%20Blood%20&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
https://www.uclahealth.org/lungcancer/coughing-up-blood-hemoptysis