Bronchitis is an infection of the main airways of the lungs (bronchi).
The main airways branch off on either side of your windpipe (trachea). They lead to smaller and smaller airways inside your lungs called bronchioles.
The walls of the main airways produce mucus to trap dust and other particles that could otherwise cause irritation.
Bronchitis happens when an infection irritates and inflames the airways. This causes them to produce more mucus than usual. Your body tries to shift this extra mucus through coughing.
Bronchitis can be either acute bronchitis or chronic bronchitis.
Acute bronchitis is temporary inflammation of the airways, causing a cough and mucus. It lasts up to 3 weeks. It can affect people of all ages, but mostly happens in children under 5. It's more common in winter and often comes on after a common cold, sore throat or flu.
Chronic bronchitis is a daily productive cough that lasts for 3 months of the year and for at least 2 years in a row. It's one of a number of lung conditions that are collectively known as chronic obstructive pulmonary disease (COPD). It mostly affects adults over 40.
If you have a high temperature, a new, continuous cough or a loss or change to your sense of smell or taste, it could be COVID-19.
Read more about symptoms of COVID-19
Symptoms of bronchitis
The main symptom of acute bronchitis is a hacking cough. This cough may bring up clear, yellow-grey or greenish mucus (phlegm).
Other symptoms are like those of the common cold or sinusitis, and may include:
- a sore throat
- a headache
- a runny or blocked nose
- aches and pains
If you have acute bronchitis, your cough may last for several weeks after other symptoms have gone.
The continual coughing makes your chest and stomach muscles sore.
Some people may have shortness of breath or wheezing as a result of inflamed airways. This is more common with long-term (chronic) bronchitis.
When to contact your GP
Most cases of acute bronchitis can be treated at home with rest, non-steroidal anti-inflammatory drugs (NSAIDs) and plenty of fluids.
You only need to contact your GP if your symptoms are severe or unusual.
For example, contact your GP if:
- your cough is severe or lasts longer than 3 weeks
- you have a high temperature for more than 3 days – this may be a sign of flu or a more serious condition
- you cough up mucus streaked with blood
- you have an underlying heart or lung condition, such as asthma, heart failure or emphysema
- you're becoming more breathless
- you have had repeated episodes of bronchitis
A GP may need to rule out other lung infections, such as pneumonia, which has similar symptoms. If they think you may have pneumonia, you'll probably need a chest x-ray and a sample of mucus may be taken for testing.
If a GP thinks you might have an underlying condition, they may also suggest that you have a lung function test.
You'll be asked to take a deep breath and blow into a device called a spirometer. This measures the volume of air in your lungs. Decreased lung capacity can be a sign of an underlying health problem.
Causes of bronchitis
Viral and bacterial infections
Bronchitis is usually caused by a virus. Less often, it's caused by a bacteria.
In most cases, bronchitis is caused by the same viruses that cause the common cold or flu.
The virus is contained in the millions of tiny droplets that come out of the nose and mouth when someone coughs or sneezes.
These droplets typically spread about 1 metre. They hang suspended in the air for a while, then land on surfaces, where the virus can survive for up to 24 hours.
Anyone who touches these surfaces can spread the virus by touching something else.
Breathing in irritant substances
Bronchitis can be triggered by breathing in irritant substances, such as smog, chemicals in household products or tobacco smoke.
Smoking is the main cause of chronic bronchitis. It can affect people who inhale secondhand smoke, as well as those who smoke themselves.
People with chronic bronchitis often develop another smoking-related lung disease called emphysema. The air sacs inside the lungs become damaged, and this causes shortness of breath.
Smoking and bronchitis
It's important that you stop smoking if you have bronchitis.
Smoking aggravates bronchitis and increases your risk of developing emphysema.
Stopping smoking while you have bronchitis can also be the perfect opportunity to quit altogether.
Cigarette smoke and the chemicals in cigarettes make bronchitis worse. They can increase your risk of developing chronic bronchitis and COPD. A GP or HSE Quit Team can also help you give up smoking.
You may also be at risk of chronic bronchitis and other types of COPD if you're often exposed to materials that can damage your lungs, such as:
- grain dust
- textiles (fabric fibres)
- strong acids
This is sometimes known as occupational bronchitis. It usually eases once you're no longer exposed to the irritant substance.
In most cases, acute bronchitis clears up by itself within a few weeks without the need for treatment. In the meantime, you should drink lots of fluid and get plenty of rest.
In some cases, the symptoms of bronchitis can last much longer. If symptoms last for at least 3 months, it's known as chronic bronchitis.
There's no cure for chronic bronchitis, but some lifestyle changes can help ease your symptoms, such as:
- eating a healthy diet
- regular moderate exercise
- avoiding smoking
There are several medicines to relieve symptoms.
Medicines called bronchodilators and steroids "open up" the airways. These can be taken as an inhaler or as tablets.
Mucolytic medicines thin the mucus in the lungs, making it easier to cough up.
Managing symptoms at home
If you have acute bronchitis:
- get plenty of rest
- drink lots of fluid – this helps prevent dehydration and thins the mucus in your lungs, making it easier to cough up
- treat headaches, a high temperature, and aches and pains with paracetamol or ibuprofen.
Ibuprofen is not recommended if you have asthma
There's little evidence that cough medicines work.
Find out more about treating coughs
Health Products Regulatory Authority (HPRA) - hpra.ie has recommended that over-the-counter cough medicines should not be given to children under the age of 6.
Children aged 6 to 12 should only use them on the advice of a doctor or pharmacist.
You can also make an alternative to cough medicine at home, using honey and lemon. This can help soothe a sore throat and ease your cough.
Antibiotics are not routinely prescribed for bronchitis because it's normally caused by a virus.
Antibiotics have no effect on viruses.
A GP will only prescribe antibiotics if you have an increased risk of developing complications, such as pneumonia.
Complications of bronchitis
Pneumonia is the most common complication of bronchitis.
It happens when the infection spreads further into the lungs, causing the tiny air sacs inside the lungs to fill up with fluid. About 1 in 20 cases of bronchitis lead to pneumonia.
People at an increased risk of developing pneumonia include:
- elderly people
- people who smoke
- people with other health conditions, such as heart, liver or kidney disease
- people with a weakened immune system
You can usually treat mild pneumonia with antibiotics at home. More severe cases may need admission to hospital.
Content supplied by the NHS and adapted for Ireland by the HSE