What a cough is and how it varies
A cough is a protective reflex: it clears mucus, irritants and foreign particles from the airways. It can be dry, with no phlegm, or wet, with phlegm. By length it is called acute, up to three weeks, or persistent, longer than three weeks. Most acute coughs come from a viral cold and clear up on their own. A persistent cough should be sorted out by a doctor, because it has many possible causes. A diagnosis cannot be made from a text.
Dry cough
A dry cough is common at the start of a viral infection, with irritation from smoke and dusty or dry air, and with allergy and asthma. It can occur with reflux, when stomach contents come back up into the food pipe and irritate the throat: see Heartburn. For some people a medicine is the cause, so tell the doctor everything you take. If a dry cough comes with a runny nose, see Runny nose, and for a sore throat, see Sore throat.
Wet cough with phlegm
A cough with phlegm is typical of bronchitis and other airway infections. The color of the phlegm, yellow or green, does not on its own prove a bacterial infection. It is more worrying when a wet cough comes with a high fever, chest pain and shortness of breath: this can happen with pneumonia, one cause of which is pneumococcus. Phlegm with blood needs urgent attention.
Cough lasting more than three weeks
If a cough does not go away after three weeks, see a general practitioner. Persistent cough can come from asthma, allergy, reflux, smoking, mucus dripping down the back of the throat from the nose, and the aftermath of an infection. Less often the cause is tuberculosis, especially when a cough comes with unexplained weight loss, night sweats and a fever. Do not delay the visit if you notice blood in phlegm, chest pain, trouble breathing or a painful swelling on the side of the neck.
Cough at night and in the morning
A cough gets worse at night because of mucus draining down the throat when you lie down, reflux and dry air in the room. A cough at night and after exercise, especially with wheezing, can be a sign of asthma. A morning cough with phlegm is common in smokers. If a cough keeps you awake for more than a few nights, see a doctor.
Cough with a fever
A cough with a high fever, body aches and weakness often goes with influenza and other viral infections. For more on fever, see Fever. If the fever lasts several days, or shortness of breath or chest pain appears, a doctor needs to examine you.
Cough in a child
Most often a child's cough comes from a viral cold. But with shortness of breath, wheezing, noisy breathing in, blue lips, or being unable to eat or talk because of difficult breathing, help is needed urgently. If a child choked and the cough does not stop after that, a foreign object may have entered the airway. Fits of coughing one after another, to the point of vomiting, with a long drawn-in breath, especially in an infant, can be a sign of whooping cough: tell the pediatrician and ask about vaccinations. A child under three months with a cough is best seen by a doctor the same day. See a pediatrician.
What you can do before the visit
- Drink enough fluids, rest, air out the room and add moisture to the air.
- Adults and children over one year can drink warm water with honey and lemon. Do not give honey to children under one year.
- Do not smoke, and avoid smoke and strong smells.
- Do not give children cough medicine unless a doctor prescribes it. Only a doctor prescribes antibiotics, and they do not help a viral cough.
- If warning signs appear, do not wait: see a doctor or call 112.
- Note when the cough began, whether it is dry or wet, when it gets worse and what else bothers you.
How a doctor finds the cause of a cough
The doctor asks about the cough, smoking, medicines and contact with sick people, listens to the lungs and measures the oxygen level in your blood. For a persistent cough they may order a chest X-ray, a phlegm test, a lung function test and allergy tests, and for suspected tuberculosis, special tests. Treatment depends on the cause: sometimes fluids and time are enough, and sometimes asthma, reflux or an infection needs treating.