A Cough That Won't Go Away

Almost everyone coughs sometimes. Most coughs come from colds, allergies, or acid reflux, and they clear up on their own. A cough that lasts, or hoarseness that will not go away, can be a warning sign worth checking. It can point to lung, throat, or voice-box cancer, though most lasting coughs are still not cancer.

A cough tied to a cold usually fades within a couple of weeks. A cough that lasts longer, especially beyond about three weeks, is the pattern doctors want to know about. So is a cough that changes character — becoming deeper, more frequent, or bringing up blood. A cough that comes with unexplained weight loss, chest pain, or shortness of breath adds to the concern.

A persistent cough is a common sign of lung cancer. It can happen because a tumor irritates the airway or partly blocks it. Ongoing hoarseness, or a voice that has changed and does not go back to normal, can be a sign of cancer of the throat or voice box, called the larynx. These cancers are more common in people who smoke or drink heavily, though they can occur without either risk factor.

Coughing up blood, even a small streak, should always be checked promptly. It has causes other than cancer, including infections and bronchitis, but it needs medical evaluation without delay rather than a wait-and-see approach.

Colds, seasonal allergies, and asthma cause the great majority of lasting coughs. Acid reflux can trigger a cough, especially at night, when stomach acid backs up toward the throat. Smoking is one of the most common causes of a chronic cough, and it is also the leading cause of lung cancer. Certain blood pressure medicines list a dry cough as a known side effect.

Your doctor asks how long the cough has lasted, whether anything is coughed up, and about your smoking history. A chest x-ray is usually the first imaging test, since it is quick and can show many lung problems, including some tumors. If the x-ray raises questions, or the cough continues without an answer, a CT scan gives a more detailed picture. If something concerning is found, doctors may use a bronchoscopy: a thin, flexible tube with a light and camera passed into the airways to look directly and take a tissue sample. The pathologist typically sends the report to your doctor within 10 days of the biopsy, according to NCI.

A chest x-ray that looks clear is reassuring but does not catch every small or early finding. If a cough lasts more than three weeks despite a normal x-ray, ask whether a CT scan makes sense, especially if you smoke or have smoked in the past.

• Call 911 or go to an emergency department if you cough up more than a streak of blood, or you are suddenly short of breath or have chest pain that makes it hard to finish a sentence.
• Call your care team the same day if there is any blood at all in what you bring up, even one streak in the mucus.
• Call your care team within a day or two if a cough or a hoarse voice has run past about three weeks, or the cough has turned deeper or more frequent alongside weight loss you did not intend.

• Should my lasting cough be evaluated with a chest scan?
• Could this be caused by something other than cancer?
• Given my smoking history, am I at higher risk?
• What symptoms should prompt an urgent visit?

• National Cancer Institute — Non-Small Cell Lung Cancer Treatment (PDQ)
• American Cancer Society — Signs and Symptoms of Laryngeal and Hypopharyngeal Cancer
• National Cancer Institute — Pathology Reports