Persistent Cough
How long a cough should last, when a lingering cough needs a doctor, and which features need urgent care.
Last revised
Most coughs follow a viral infection and settle within about three weeks, though a cough after a cold can linger for up to eight. A cough lasting more than three weeks without an obvious cause should be checked by a doctor.
When a cough has gone on too long
A cough that lasts longer than three weeks is a reasonable point to see your doctor, and one lasting more than eight weeks is considered chronic. The reason is straightforward: most long coughs have treatable causes, and a persistent cough is also the most common first symptom of lung cancer, where the stage at diagnosis dominates the outcome. Adults aged 50 to 80 with a heavy smoking history may be eligible for yearly lung cancer screening with a low-dose CT scan.
Common causes of a long cough
Airway irritation after an infection, which can take six to eight weeks to settle. Asthma, particularly if the cough is worse at night or with exercise. Reflux, often with a sour taste or a cough when lying flat. Postnasal drip. ACE inhibitor medicines, which cause a characteristic dry cough in a minority of people and resolve on switching. Smoking itself.
Dry versus productive
A dry cough points more toward irritation, asthma, reflux or medication. A cough bringing up discolored mucus most often follows infection, but coughing up mucus most days for months suggests chronic bronchitis or bronchiectasis and should be investigated. Coughing up blood, in any amount, always needs a doctor.
Children
Children get frequent coughs, and a cough lasting a couple of weeks after a cold is normal. A child needs to be seen for a cough with noisy breathing or wheezing, a barking cough with difficulty breathing, coughing that started suddenly after possibly inhaling a small object, or any cough in a child who is not feeding or is unusually drowsy.
At a glance
| Term | Detail |
|---|---|
| Typical viral cough | settles within about 3 weeks |
| Cough after a cold | can persist 6-8 weeks |
| See a doctor if a cough lasts | more than 3 weeks |
| Chronic cough | more than 8 weeks in adults |
| Common medicine cause | ACE inhibitors, causing a dry cough |
| Always needs a doctor | coughing up blood, in any amount |
| Lung cancer screening | yearly low-dose CT for eligible adults 50-80 with a heavy smoking history |
When to get help
See your doctor for a cough lasting more than three weeks, or sooner if you cough up blood, lose weight without trying, have night sweats, chest pain, hoarseness lasting three weeks, or increasing shortness of breath. Call 911 for severe difficulty breathing, blue or gray lips, confusion, or a child who is struggling to breathe, grunting, limp or hard to wake.
Where this comes from
- CDC - Chest Cold (Acute Bronchitis)
- MedlinePlus - Cough
- US Preventive Services Task Force - Lung Cancer: Screening
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
