What is bronchitis?
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Bronchitis is an infection of the main airways of the lungs (bronchi), which causes them to become irritated and inflamed.
The main symptom is a cough which may bring up yellow-grey mucus. Bronchitis may also cause a sore throat, wheezing and a blocked nose.
Read more about the symptoms of bronchitis.
When to see your doctor
Most cases of bronchitis can be treated easily at home.
You only need to see your doctor if your symptoms are severe or unusual – for example, if:
- your cough is severe or lasts longer than three weeks
- you have a constant fever for more than three days
- you cough up mucus streaked with blood
- you have an underlying heart or lung condition, such as asthma or heart failure
In most cases bronchitis will clear up by itself within a few weeks without the need for treatment. This type of bronchitis is known as acute bronchitis. While you are waiting for it to pass, 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 three months, this is known as chronic bronchitis. There is no cure for chronic bronchitis but there are several medications to help relieve symptoms. It is also important to avoid smoking and smoky environments, as this can make your symptoms worse.
Read more about treating bronchitis.
Why do I have bronchitis?
The bronchi are the main airways in your lungs, which branch off on either side of your windpipe (trachea). They lead to smaller and smaller airways inside your lungs, known as bronchioles.
The walls of the bronchi produce mucus to trap dust and other particles that could otherwise cause irritation.
Most cases of acute bronchitis develop when an infection causes the bronchi to become irritated and inflamed, which causes them to produce more mucus than usual. Your body tries to shift this extra mucus through coughing.
Smoking is the most common cause of chronic bronchitis. Over time, tobacco smoke can cause permanent damage to the bronchi, causing them to become inflamed.
Read more about the causes of bronchitis.
Pneumonia is the most common complication of bronchitis. It happens when the infection spreads further into the lungs, causing air sacs inside the lungs to fill up with fluid. One in 20 cases of bronchitis leads to pneumonia.
People more vulnerable to the effects of infection, such as the very young or people with a pre-existing health condition, may need to be admitted to hospital as a precaution if they develop pneumonia.
Read more about the complications of bronchitis.
Who is affected
Acute bronchitis is one of the most common types of lung infection and one of the top five reasons for doctor visits.
Acute bronchitis can affect people of all ages but it is most common in younger children under the age of five. It is more common in winter and often develops following a cold, sore throat or flu.
It is estimated that there are around 2 million people in the UK affected by chronic bronchitis. Most of these are adults over the age of 50.
The main symptom of bronchitis is a hacking cough. It is likely that your cough will bring up thick yellow-grey mucus, although this does not always happen.
Your cough may last for several weeks after other symptoms have gone, and you may find the continual coughing makes your chest and stomach muscles sore.
Other symptoms of bronchitis may include:
- a tight feeling in your chest
- sore throat
- slight fever and chills
- blocked nose and sinuses
- aches and pains
Although unpleasant, these symptoms are usually not severe and you may not need to see your doctor. However, the symptoms of bronchitis can be similar to those of pneumonia (an infection that causes inflammation in your lungs), so it is important to look out for any changes in your symptoms.
When to see your doctor
See your doctor as soon as possible if:
- your cough is very severe or lasts longer than three weeks
- you have a constant fever for more than three days
- you cough up mucus streaked with blood
- you develop rapid breathing (more than 30 breaths a minute) or chest pains
- you become drowsy or confused
- you have had repeated bouts of bronchitis
- you have an underlying heart or lung condition, such as asthma, emphysema (damage to the small airways in your lungs), congestive heart failure (weakness in the heart that leads to fluid in your lungs) or chronic obstructive pulmonary disease (long-term lung damage)
You should also contact your doctor for advice if you have an underlying heart or lung condition that can make you more vulnerable to the effects of infection, such as asthma or heart failure.
Long-term (chronic) bronchitis
The symptoms of chronic bronchitis are often worse in the winter and it is common to have two or more flare-ups a year. A flare-up is when your symptoms are particularly bad.
If you have chronic obstructive pulmonary disease (chronic bronchitis combined with emphysema), you will be increasingly breathless when exercising or moving around.
Read more about the symptoms of chronic obstructive pulmonary disease.
The bronchitis infection can be caused by either a virus or bacteria, although viral bronchitis is much more common.
In most cases, bronchitis is caused by the same viruses that cause the common cold or influenza (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 1m (3ft). 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 further by touching something else.
Everyday items at home and in public places, such as door handles and keyboards, may have traces of the virus on them. People usually become infected by picking up the virus on their hands from contaminated objects and then placing their hands near their mouth or nose. It is also possible to breathe in the virus if it is suspended in airborne droplets.
Breathing in irritant substances
Bronchitis can also be triggered by breathing in irritant substances, such as smog, chemicals in household products or tobacco smoke.
Smoking is the main cause of chronic (long-term) bronchitis, and it can affect people who inhale second-hand smoke as well as smokers themselves.
You may also be at risk of bronchitis if you are often exposed to materials that can damage your lungs, such as grain dust, textiles (fabric fibres), ammonia, strong acids or chlorine. This is sometimes referred to as occupational bronchitis, and usually eases once you are no longer exposed to the irritant substance.
If you have bronchitis, you may not need to see your doctor unless your symptoms are severe or persistent (read more about when to see your doctor).
If you do see your doctor, they will usually be able to make a diagnosis by asking about your symptoms and listening to your chest using a stethoscope.
Ruling out other conditions
Your doctor may need to rule out other lung infections, such as pneumonia, which has symptoms similar to those of bronchitis. If your doctor thinks you may have pneumonia, you will probably need a chest X-ray. Your doctor may also take a sample of mucus for testing.
If your doctor thinks that you may have an undiagnosed underlying condition, such as asthma or emphysema (damage to the small airways in your lungs), they may also suggest a pulmonary function test. You will be asked to take a deep breath and blow into a device called a spirometer, which measures the volume of air in your lungs. A decreased lung capacity can indicate an underlying health problem.
Treatment for bronchitis
Most cases of bronchitis do not require treatment from a doctor and the symptoms can be easily managed at home.
There is no cure for chronic bronchitis but healthy living will help. In particular, you should stop smoking if you smoke.
Managing symptoms at home
If you have bronchitis:
- Get plenty of rest.
- Drink lots of fluids. This helps prevent dehydration and thins the mucus in your lungs, making it easier to cough up.
- Treat headaches, fever, and aches and pains with paracetamol or ibuprofen (ibuprofen is not recommended if you have asthma).
There is little evidence that cough medicines work (read more about treating coughs) and the Medicines and Healthcare products Regulatory Agency (MHRA) has recommended that over-the-counter (OTC) cough medicines should not be given to children under the age of six.
As an alternative to an OTC cough medicine, try making your own mixture of honey and lemon, which can help soothe a sore throat and ease your cough.
If you smoke, you should stop immediately. Smoking aggravates bronchitis and increases your risk of developing a chronic (long-term) condition. Stopping smoking while you have bronchitis can also be the perfect opportunity to quit altogether.
Although treatment from a doctor is rarely necessary, there may be times when you should see your doctor (read more about when to see your doctor).
Your doctor will not routinely prescribe antibiotic treatment as bronchitis is nearly always caused by a virus. Antibiotics have no effect on viruses, and prescribing them when they are unnecessary can, over time, make bacteria more resistant to antibiotic treatment.
Your doctor will only prescribe antibiotics if you have an increased risk of developing complications, such as pneumonia. Antibiotics may be recommended for:
- premature babies
- elderly people over the age of 80
- people with a history of lung, heart, kidney or liver disease
- people with a weakened immune system, which could be the result of an underlying condition or a side effect of a treatment such as steroid medication
- people with cystic fibrosis
If you are prescribed antibiotics for bronchitis, it is likely to be a five-day course of amoxicillin, oxytetracycline or doxycycline.
Possible side effects of these medicines include nausea, vomiting and diarrhoea, but they are uncommon.
Chronic bronchitis is treated in the same way as chronic obstructive pulmonary disease (COPD).
- a type of medication called mucolytics can be used to make mucus easier to cough up
- an exercise programme known as pulmonary rehabilitation can help you cope better with your symptoms
Stopping smoking is also very important if you have been diagnosed with chronic bronchitis or COPD.
Read more about the treatment of chronic obstructive pulmonary disease.
Alberta Clinical Practice Guideline Working Group. (2006). Guideline for the Management of Acute Bronchitis [online], Alberta Medical Association [Accessed 29th Jan 2008].
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BMJ Best Treatments (2008). Bronchitis (Cough) [online].
The following advice may help prevent bronchitis.
- Stop smoking. Tobacco smoke can make a current infection worse and makes you much more likely to develop chronic bronchitis.
- Maintain good hygiene. Bronchitis is usually caused by a virus, which spreads through either direct contact or through coughing and sneezing. Washing your hands often and using disposable tissues can help prevent the spread of infection.
- Protect yourself at work. If you work with substances that can irritate your lungs, always wear a mask that covers your nose and mouth.
Around one person in 20 with bronchitis goes on to develop a secondary infection inside one or both of their lungs. Specifically, the infection takes hold in tiny air sacs known as alveoli. This type of infection is called 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
Symptoms of pneumonia include:
- difficulty breathing – your breathing may be rapid and shallow and you may feel breathless, even when you are resting
- rapid heartbeat
- feeling generally unwell
- sweating and shivering
- loss of appetite
- pain in your chest
Mild pneumonia can usually be treated with antibiotics at home.
More severe cases may require admission to hospital where, if necessary, a breathing machine (ventilator) can assist you with your breathing and antibiotics can be given directly into one of your blood vessels through a drip.
Read more about the treatment of pneumonia.