Symptom
Persistent Cough: When It's Worth Investigating
You've had a cough that won't go away and you want to know whether to worry.
Educational, not diagnostic. This page won't tell you whether you have cancer. It will help you have a more productive conversation with your physician. For emergencies, call 911.
A cough lasting more than 8 weeks is considered chronic. The vast majority are caused by post-nasal drip, asthma, acid reflux, or ACE-inhibitor blood pressure medications.
Lung cancer is a less common cause but worth ruling out, especially in current or former smokers, people with significant secondhand smoke or radon exposure, or those with a family history.
The first test for any persistent cough is usually a chest X-ray. If you're 50–80 with a significant smoking history, you may also be eligible for a low-dose CT screening — covered by Medicare and most insurance.
Common causes — most are not cancer
Post-nasal drip
The single most common cause of chronic cough. Often improves with nasal sprays or antihistamines.
Asthma or cough-variant asthma
Cough may be the only symptom, especially at night or with exercise.
Acid reflux (GERD)
Stomach acid irritating the airway causes a dry, persistent cough often worse when lying down.
ACE inhibitor medications
Lisinopril and similar blood pressure medications cause a dry cough in up to 20% of users.
Chronic bronchitis
Common in current or former smokers; productive cough with mucus.
Lung cancer
Less common but important to rule out, especially with risk factors or red-flag symptoms.
- Cough lasting more than 8 weeks
- Coughing up blood, even small streaks
- Unexplained weight loss with the cough
- New shortness of breath or chest pain
- Hoarseness lasting more than 3 weeks
- Smoking history of 20+ pack-years (eligible for CT lung screening)
What a proper work-up looks like
- 1
Targeted history
Smoking, occupational exposures, allergies, reflux symptoms, and current medications.
- 2
Chest X-ray
First-line imaging for any persistent cough; often sufficient to rule out the most concerning causes.
- 3
Low-dose CT
For smokers 50–80 with 20+ pack-years, this screening test catches lung cancer at curable stages.
- 4
Pulmonary referral or biopsy
For nodules, masses, or unclear findings — interventional pulmonology or thoracic surgery becomes involved.
Questions worth bringing to your appointment
- Am I eligible for low-dose CT lung cancer screening?
- Could one of my current medications be causing this?
- What would change your thinking about further testing?
- Should I see a pulmonologist?
Frequently asked questions
Can lung cancer cause a cough without other symptoms?
Yes. Early lung cancer is often silent or causes only a mild change in a long-standing cough. That's why screening with low-dose CT is so important for high-risk patients.
Who qualifies for lung cancer screening?
Generally adults 50–80 who currently smoke or quit within the last 15 years, with a 20-pack-year history. Medicare and most insurance cover annual low-dose CT for these patients.
Should I be worried if I never smoked?
Lung cancer in never-smokers exists but is less common. Red flags — coughing up blood, weight loss, persistent hoarseness — still deserve evaluation regardless of smoking history.
Insurance accepted
Coverage details vary by plan. Our care coordinators help verify your benefits before scheduling.
Want a calm, expert opinion on what's going on?
Request a new patient consultation or independent second opinion with Keck Medicine of USC — Newport Beach. Most major insurance accepted.