Persistent cough, dry cough or wet cough: causes and when to worry

A cough is an important way your body keeps your throat and airways clear. Coughing now and then is normal; coughing a lot, or for weeks, can be a sign of a condition that needs treatment. Doctors group coughs by how long they last:

• Acute cough: starts suddenly, usually from a cold, flu or sinus infection, and generally goes away within 3 weeks.
• Subacute cough: lasts 3 to 8 weeks, often the cough left behind after an infection.
• Chronic cough: lasts more than 8 weeks and always deserves a medical evaluation to find the cause.

For your safety, call 911 if you are short of breath or struggling to breathe, or have hives with a swollen face or throat and trouble swallowing. Go to the ER if you cough up blood or have chest pain. Contact your doctor right away if a cough comes with a high fever, a high-pitched sound when breathing in or thick, foul-smelling mucus; gets worse lying down and you have a heart condition or swollen legs; comes with unintended weight loss and night sweats; or if you may have been exposed to tuberculosis. A baby under 3 months with a cough needs care right away. See when to go to the ER.

You don’t have to wait for a cough to become chronic (more than 8 weeks) to get checked. Besides the warning signs above, MedlinePlus advises contacting your doctor right away if:

• Your cough lasts more than 10 to 14 days.
• You have a fever along with the cough.

A dry cough brings nothing up. It is common with allergies, asthma, acid reflux, irritation from smoke or dust, and the tail end of a cold, when the throat stays sensitive. If a dry cough comes with hoarseness, see laryngitis.

A wet cough (a cough with mucus, also called a productive cough) usually goes with a respiratory infection such as a cold, bronchitis or a sinus infection with postnasal drip. Mucus color alone does not tell you whether you need an antibiotic, and most viral coughs get better without one. Get checked if the mucus is bloody or foul-smelling, or if you have a fever.

The causes table on this page sums up the usual suspects. A few clues:

• Cough with fever and body aches: flu or COVID-19.
• A wet cough that lingers after a cold: possibly bronchitis.
• A dry cough with sneezing and itchy nose or eyes: possibly allergies.
• A cough with wheezing, worse at night or with exercise: possibly asthma.
• A cough with heartburn, worse lying down: possibly acid reflux.
• Mucus dripping down the throat and facial pressure: possibly a sinus infection.
• Coughing fits of many rapid coughs, sometimes with a "whoop" when breathing in or vomiting afterward: possibly whooping cough, especially if someone at home has a similar cough.
• A cough with mucus on most days in someone who smokes, often called a smoker’s cough: possibly chronic bronchitis. According to MedlinePlus, if you smoke, quitting is the most important step to treat it.
• A cough that started with a new blood pressure medicine: tell the doctor, because some medicines cause a cough.

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For a cough from a cold or flu without warning signs:

• Drink plenty of fluids to help loosen mucus.
• Breathe steam from a warm shower or use a humidifier.
• A spoonful of honey can ease a cough in adults and children 1 year and older. Never give honey to a baby under 12 months.
• Cough drops or hard candy can ease a dry cough in adults. Never give them to children under 4, who can choke on them.
• Stay away from cigarette smoke and vaping.
• If you use over-the-counter cough or decongestant products, read the label, especially if you have high blood pressure or another condition.
• If a cough lasts more than 10 to 14 days, comes with fever, or the doctor suspects another cause, she will decide whether you need tests. If needed, she gives you a lab order; if you need an X-ray or an in-person chest exam, she refers you and points you to the right place.

We see children of all ages too; for patients under 21, a parent or legal guardian stays on camera for the whole visit and shows photo ID. Children follow different rules: over-the-counter cough and cold medicines are not recommended under age 4, and honey must not be given to babies under 12 months. Read cough in children.