Coughs are grouped by how long they last. An acute cough (under 3 weeks) is most often viral and settles as the airway heals. A lingering cough for several weeks after an infection is also common as the airways stay irritated. Other frequent causes of an ongoing cough include post-nasal drip from allergies or sinus issues, asthma, acid reflux, smoking, and certain blood-pressure medicines.
A cough that lasts more than 8 weeks (chronic cough) should be assessed by a doctor to look for causes such as asthma, reflux, or, less commonly, lung disease. Seek prompt care if you cough up blood, lose weight without trying, have night sweats, drenching fevers, or increasing breathlessness — and remember that a persistent cough can be a sign of tuberculosis in some settings.
Get emergency help if you have severe difficulty breathing, chest pain, or blue lips. A pharmacist can suggest soothing remedies, but persistent or alarming coughs need a clinician. This is general information only.