A chronic cough that gets worse can be an early symptom of lung cancer. If your cough is bothersome and has been hanging on, it’s a good idea to see a doctor.

Coughs are one the most common reasons people see a doctor. While most coughs have benign causes, a severe cough that persists may indicate a more serious underlying condition.

If lung cancer is involved with the cough, the earlier it’s detected, the better the outcome. Often early lung cancer has no noticeable symptoms, so it’s usually diagnosed at an advanced stage when it’s harder to treat.

Not everyone with early lung cancer has a cough. The Lung Cancer Alliance states that about 50 percent of people have a cough in the early stage of lung cancer, before the cancer cells have spread to other parts of the body.

A 2017 study reports that about 57 percent of people with lung cancer have a cough. In late-stage lung cancer, the percentage is higher. According to a 2018 report, up to 90 percent of people with advanced lung cancer have a cough.

Any type of lung cancer can be associated with a cough. But some forms of lung cancer more often have a cough as a symptom because the cancerous cells are obstructing the airways in your lungs. Squamous cell carcinoma and small cell undifferentiated lung cancer are more likely to be associated with a cough.

There’s no simple way to tell if lung cancer is the cause of your cough. Your cough may be benign, or may be associated with any number of underlying diseases. Doctors use professional guidelines to diagnose and treat coughs.

Your doctor will ask about your medical and smoking history to begin to determine the cough’s cause. They’ll ask about other accompanying symptoms, such as fever, cold, fatigue, shortness of breath, hoarseness, chest pain, or weight loss. They’ll also want to know when your cough began, whether it’s worse at night, and when it got worse or developed new features.

If the doctor suspects lung cancer, they’ll order screening and other tests to confirm a diagnosis.

A 2005 study that looked at the symptoms of British lung cancer patients at the time of their diagnosis found that in addition to cigarette smoking, there were seven common symptoms associated with lung cancer at diagnosis:

  • spitting up blood (hemoptysis)
  • weight loss
  • loss of appetite
  • difficulty breathing (dyspnea)
  • chest pain
  • cough
  • fatigue

The strongest associations with lung cancer, in addition to smoking, were:

  • spitting up blood
  • difficulty breathing
  • abnormal breathing patterns

Coughs, both acute and chronic, can have many causes. An acute cough is defined as lasting less than three weeks. A chronic cough is one that lasts more than eight weeks.

The most common causes of an acute cough are upper respiratory tract infections and acute bronchitis. One study found that these were responsible for more than 60 percent of diagnosed acute coughs.

The most common causes of a chronic cough are:

Other less common causes include bronchial diseases, cystic fibrosis, whooping cough, lung inflammation, and heart failure.

Having a persistent cough is one of the early symptoms of lung cancer, before the cancer has spread (metastasized) beyond your lungs. About half of the people with early lung cancer have a chronic cough.

In one study, coughing up blood was the strongest predictor of lung cancer, but fewer than 5 percent of people reported it as an early symptom.

Other symptoms of lung cancer include:

  • changes in your cough’s intensity or production of mucus
  • increasing shortness of breath (dyspnea)
  • pain in the chest, shoulders, or back
  • wheezing
  • fatigue
  • hoarseness or other changes in your voice
  • pneumonia or other recurrent lung problems
  • weight loss

Once the cancerous cells have metastasized to other parts of your body, you may have other symptoms. The most common places that lung cancer spreads are other areas of your lungs, lymph nodes, bones, brain, liver, and adrenal glands.

Symptoms of metastasized lung cancer include:

  • bone pain or joint pain
  • headaches, if your brain is infected
  • swelling in your neck or face
  • loss of appetite
  • weakness and fatigue

You may have other symptoms, depending on the organ where the cancer has spread.

If you’re worried about a lingering cough, see a doctor to discuss possible causes and treatment. If you’re coughing up blood, see a doctor right away.

If lung cancer is suspected because of your symptoms or your lung cancer risk, there are many tests your doctor may order to determine if it’s cancer or something else. Diagnostic tests include:

Depending on the stage of your lung cancer and your general health, you may have surgery to remove the cancerous lung tumor. You may also have chemotherapy, radiation, or other treatments to relieve pain and kill the cancer cells.

But sometimes these treatments may not relieve your cough. In some cases, a cough may be a side effect of the lung cancer treatment.

A chronic cough with lung cancer can be exhausting. It can cause headaches, dizziness, sweating, loss of appetite, and sleep loss. Conventional treatments are drugs to suppress coughing and relieve pain.

A 2017 study noted that cough is often an undertreated symptom of lung cancer. To remedy the situation, this study updated the American College of Chest Physicians (CHEST) guidelines to give doctors a specific step-by-step approach to managing lung cancer coughs.

The study recommendations include:

  • identification and treatment of any coexisting conditions associated with your cough
  • cough suppression exercises
  • endobronchial-brachytherapy, a new treatment that focuses high-dose radiation on tumors
  • use of demulcents, substances that coat and soothe mucous membranes
  • use of opiates, when other remedies have failed
  • use of other drugs, such as levodropropizine, moguisteine, levocloperastine, or sodium cromoglycate
  • use of local anesthetics, such as lidocaine/bupivacaine or benzonatate
  • participation in randomized controlled trials of new drugs that may help control a cough, such as diazepam, gabapentin, carbamazepine, baclofen, amitriptyline, and thalidomide

If you have a lingering chronic cough, see your doctor to find out the cause and possible treatments. The earlier lung cancer is detected, the better your chances for recovery. There aren’t yet any cures for metastasized lung cancer, so early diagnosis is key.