Cough: Types, Causes and When to See a Doctor

Types of cough

Doctors ask three questions to classify a cough: how long, wet or dry, and what it sounds like.

By duration

Dry vs wet (productive) cough

• Dry cough: no phlegm, often a tickle in the throat. Typical of viral infections, asthma, reflux, ACE inhibitor medicines and early COVID-19. See dry cough.
• Wet or productive cough: brings up mucus (sputum) from the chest. Typical of chest infections, COPD and bronchiectasis. See productive cough.

By sound

• Barking, seal-like: croup in young children.
• Whooping: a run of coughs followed by a gasping "whoop", typical of whooping cough.
• Wheezy: asthma, bronchiolitis, COPD.
• Throat-clearing, worse lying down: postnasal drip or reflux.

Cough with sputum: what the color and texture mean

A loose cough in the morning that brings up frothy or gray mucus is typical of smokers and people with chronic bronchitis or COPD, because mucus pools overnight. Coughing up lumpy gray or porridge-like material can be caused by smoking or dust, or occasionally by tonsil debris or food aspiration, and should be checked if it persists.

Common causes of cough

Infections

Viral colds, flu and COVID-19 cause most acute coughs. A chest cold (acute bronchitis) can leave a cough for 3 weeks or more. Pneumonia causes cough with fever, chills, fast breathing and sometimes sharp chest pain.

Postnasal drip

Mucus dripping from the nose and sinuses irritates the throat. You may feel the need to clear your throat often, especially at night.

Asthma

Asthma can show up only as a dry cough (cough-variant asthma), worse at night, with exercise, cold air or allergens.

Reflux

Gastroesophageal reflux disease can cause a chronic dry cough, often after meals or on lying down. Heartburn may or may not be present.

Smoking and COPD

A daily wet cough, especially in the morning, is a hallmark of COPD. A change in a long-standing smoker's cough is a reason to get checked for lung cancer.

Medicines

ACE inhibitors (such as lisinopril and ramipril) cause a dry cough in a minority of users. It can start weeks or months after starting and fades within weeks of stopping.

Serious but less common causes

• Heart failure: cough lying flat, frothy sputum, ankle swelling.
• Lung cancer: persistent cough, blood in sputum, weight loss.
• Tuberculosis: cough over 3 weeks, night sweats, weight loss.
• Pulmonary embolism: sudden breathlessness and chest pain, sometimes coughing blood.
• Inhaled foreign object: sudden cough after choking, mainly in children.

Massive coughing up of blood, which can kill quickly, is rare. It is usually caused by advanced lung cancer, tuberculosis cavities or bronchiectasis eroding a blood vessel, and needs emergency care.

Diagnosing a cough type

Your doctor will ask how long the cough has lasted, whether it is wet or dry, what the sputum looks like, what triggers it, whether you smoke, and which medicines you take. They will listen to your chest and check oxygen levels. Tests depend on the picture:

• Chest X-ray: for cough over 3 to 8 weeks, coughing blood, weight loss or abnormal chest sounds.
• Spirometry: breathing tests for asthma and COPD.
• Sputum tests: for tuberculosis or persistent infection.
• Swab tests: for flu, COVID-19 or whooping cough.
• CT scan or bronchoscopy: when cancer, bronchiectasis or a foreign body is suspected.

Treatment and home care

• Honey: a spoonful of honey, alone or in a warm drink, eases cough in adults and children over 1 year. Never give honey to babies under 12 months.
• Fluids, rest and humid air loosen mucus.
• Stop smoking: smoker's cough often improves within weeks.
• Over-the-counter cough medicines: evidence for them is weak. Follow the label dose. Do not give cough and cold medicines to children under 4 in the US (UK guidance says under 6).
• Antibiotics: do not help viral coughs or most bronchitis. They are used for confirmed or likely bacterial pneumonia, whooping cough and some COPD flares.
• Cause-specific treatment: inhalers for asthma, nasal sprays for postnasal drip, acid-reducing medicine for reflux, switching from an ACE inhibitor.

Frequently asked questions

What are the different types of cough?

Coughs are grouped by duration (acute under 3 weeks, chronic over 8 weeks), by whether they bring up sputum (dry or productive), and by sound (barking, whooping, wheezy). Together these clues point to the likely cause, such as a cold, asthma, reflux, croup or whooping cough.

What does a cough with sputum mean?

A productive cough means your airways are clearing mucus, most often from a chest cold or bronchitis. Daily sputum for months suggests COPD or bronchiectasis. Blood, rust-colored or pink frothy sputum needs medical assessment. Green sputum alone does not mean you need antibiotics.

How long is too long for a cough?

Most coughs from colds are gone within 3 weeks. See a doctor if a cough lasts more than 3 weeks, keeps getting worse, or comes with blood, breathlessness, chest pain, fever or weight loss. A cough over 8 weeks is chronic and needs a cause found.

Is a morning cough with frothy sputum normal?

It is common in smokers and people with chronic bronchitis, because mucus collects overnight. It is not normal for healthy lungs and is often an early sign of COPD. Pink frothy sputum with breathlessness is different: it can mean fluid in the lungs and needs emergency care.

Why does my cough get worse at night?

Lying down lets mucus drip down the back of the throat and lets stomach acid reflux more easily. Asthma also tends to worsen at night. Raising your head, avoiding late meals and treating any nasal congestion or asthma often helps.