What Causes Acute Bronchitis?

Understanding Bronchitis

Bronchitis is an inflammation of the lower respiratory system, sometimes referred to as a chest cold or infection. Bronchi are the main airways of the lungs, branching off from the windpipe (trachea) and leading into a tree of progressively smaller airways, or bronchioles. Inflammation of these airways is known as bronchitis. This differs from pneumonia, which is inflammation of the tissue of the lungs. When the bronchial tubes become inflamed, they become irritated, producing more mucus than normal. In response to this, your body will cause you to cough to help clear this.1 

Signs and symptoms

The most common symptom of acute bronchitis is a hacking cough. The cough may be dry or you may bring up mucus (phlegm), that can be clear, yellowish, or green. Other symptoms of bronchitis are similar to those found in the common cold or other minor respiratory illnesses, including: 

  • Cough
  • Sore throat 
  • Runny, blocked nose 
  • Headache 
  • Tiredness or feeling generally unwell 
  • Shortness of breath
  • Fever
  • Wheezing or whistling sound when you breathe.2 

What are the types of Bronchitis

The main types of bronchitis are acute and chronic. Acute bronchitis is a temporary inflammation, appearing suddenly, and lasting for no longer than 3 weeks. Chronic bronchitis is a persistent cough for at least 3 months in two consecutive years. It can occur alone or alongside emphysema in chronic obstructive pulmonary disease (COPD).1 

What are the common causes of acute bronchitis


Viruses are the main cause of chest colds and other mild respiratory illnesses. The main culprits include the influenza virus, respiratory syncytial virus (RSV), and adenovirus. Viral bronchitis is more common in the winter season. 


Bacteria such as mycoplasma pneumoniae, chlamydia pneumonia, and less often, Bordetella Pertussis can lead to bronchitis. The last type of bacterium, B. Pertussis can lead to a different disease of the lower airways: Pertussis. It is more commonly known as whooping cough due to its characteristic ‘whoop’ between coughing bouts. Whooping cough is a more serious disease than bronchitis but has fortunately reduced occurrence due to it being part of the childhood vaccination program.3

Air pollution 

Inhalation of substances that irritate the airway, such as smoke, chemicals found in household products, or fumes from industrial production cause inflammation of the bronchial tubes. This is less likely to cause acute bronchitis and is more likely to lead to COPD and chronic bronchitis from low levels of prolonged exposure.1,4 

What does it feel like when having acute bronchitis?

Before you develop acute bronchitis, you will often start with a common cold or mild flu symptoms. You may have a runny nose, sore throat, and a headache. As the infection spreads from the upper to the lower airways, this is when the symptoms of a chest cold will appear. The main symptom of bronchitis is a hacking cough, that starts off dry, then after a few days, you may start bringing up mucus. You will feel run down and not like yourself. You can have pains or discomfort in your chest which can be exacerbated by coughing. These symptoms are often mild, albeit unpleasant, but will generally pass in under a few weeks with little to no intervention. 


Despite being not serious for most people, sometimes complications of bronchitis do occur. The most common complication of acute bronchitis is pneumonia. This happens when the infection spreads from the bronchial tubes into the tissue of the lungs itself. This only happens in around 1 in 20 people and is more likely to affect those who are older, smoke, or already have weakened immune systems.1 

Sometimes after the infection has disappeared, symptoms of bronchitis, particularly the cough,  may persist. This phenomenon is known as Post Bronchitis syndrome or a postinfectious cough.5 

If you have any underlying health problems, such as lung disease, asthma, or heart failure, then acute bronchitis is liable to make these conditions worse. It is important to notify your healthcare provider of any ongoing health problems.4 

How to treat and prevent acute bronchitis

Usually, acute bronchitis does not require any medication to treat it. This is because most cases are mild enough not to require treatment, and are caused by a viral infection. Specific ways to prevent infection are: 

  • Avoiding people who are already or might be sick. 
  • Quitting smoking.
  • Avoid smoke and other irritants. If unable to do so, wearing a suitable mask over the mouth and nose to help protect your airways will help. 
  • Practicing good hand hygiene. Washing your hands with soap, or with an alcohol-based hand gel, helps ensure disease control. 
  • Receiving an annual flu vaccine.4

Natural Remedies

It is possible to help relieve symptoms of acute bronchitis at home using natural remedies. Examples include: 

  • Salt water - gargling salt water can help soothe a sore throat and break up mucus. 
  • Honey - can help a sore throat.6
  • Ginger - Has anti-inflammatory properties that can help against respiratory infection. 
  • Garlic - Has been shown to inhibit the growth of viruses in the bronchial tubes.7

Natural remedies are useful in alleviating symptoms of minor illnesses, such as bronchitis. However, they are not curative and should not be used to replace medical treatment. If symptoms worsen or persist do contact your family physician for advice. 

What you can do at home

At home, there are a few things you can do to help relieve symptoms of acute bronchitis. These include: 

  • Drinking plenty of fluids helps prevent dehydration and thins your mucus out so that it is easier to cough up. 
  • Get plenty of rest.
  • Take over-the-counter painkillers- medications referred to as ‘Nonsteroidal anti-inflammatory drugs such as Ibuprofen, Paracetamol, or Aspirin, help relieve chest pain, sore throats, and headaches. They can also help reduce your temperature if you have a fever. Do not give aspirin to children due to the risk of Reye’s syndrome
  • Have a well-balanced diet to boost your immune system. 
  • Inhaling heated, humidified air helps relieve nasal congestion and runny noses. Drinking warm drinks and taking a hot bath or shower also helps.1,3


Prescribing medication is only required in cases of severe bronchitis, or if you are more at risk of developing complications. They will be medications with either the aim of recovering from bronchitis faster or helping relieve symptoms. These include: 

  • Antibiotics - These are reserved for cases of bacterial bronchitis and are therefore rarely prescribed. Healthcare providers may give antibiotics if they have suspicions of a bacterial infection, your symptoms are not improving, or you have underlying health problems which put you at risk of developing complications. 
  • Antiviral medication - Useful if caused by the influenza virus. 
  • Anti-inflammatory medication - such as corticosteroids, will help reduce the inflammation and relieve symptoms 
  • Bronchodilators - if you are experiencing difficulty breathing, your doctor may prescribe this to you to help open up your airways. These can be given either as an inhaler or as tablets. 
  • Cough suppressants - these can be over the counter or prescribed to help relieve your cough.4

When to consult a doctor

Acute bronchitis rarely requires medical treatment. However, if you are concerned about your illness then it is always best to contact your family physician. Seek advice from your healthcare provider if you are experiencing: 

  • Cough that is lasting for longer than 3 weeks. 
  • Fever over 39℃.
  • Fever that lasts for more than 5 days 
  • Coughing up blood 
  • Shortness of breath.1,4


Acute bronchitis is inflammation of the lower respiratory tract or bronchi. In acute cases, it is often infectious, mainly caused by viruses. Its main symptom is a persistent hacking cough that can bring up mucus. Acute bronchitis starts suddenly but symptoms usually subside within 3 weeks without needing medical treatment. At-home remedies and over-the-counter treatments used to treat the common cold and other minor illnesses will help alleviate symptoms. 


  1. Bronchitis [Internet]. NHS.UK. 2017 [cited 2022 Nov 14]. Available from: https://www.nhs.uk/conditions/bronchitis/ 
  2. Acute bronchitis symptoms, causes & risk factors [Internet]. [cited 2022 Nov 14]. Available from: https://www.lung.org/lung-health-diseases/lung-disease-lookup/bronchitis/symptoms-diagnosis-treatment 
  3. Uptodate [Internet]. [cited 2022 Nov 14]. Available from: https://www.uptodate.com/contents/acute-bronchitis-in-adults-beyond-the-basics/print
  4. Bronchitis: causes, symptoms, diagnosis & treatment [Internet]. Cleveland Clinic. [cited 2022 Nov 14]. Available from: https://my.clevelandclinic.org/health/diseases/3993-bronchitis 
  5. Braman SS. Postinfectious cough. Chest [Internet]. 2006 Jan [cited 2022 Nov 14];129(1):138S-146S. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0012369215528420 
  6. Do any bronchitis home remedies actually work? [Internet]. Cleveland Clinic. 2019 [cited 2022 Nov 14]. Available from: https://health.clevelandclinic.org/bronchitis-home-remedies/ 
  7. Mohajer Shojai T, Ghalyanchi Langeroudi A, Karimi V, Barin A, Sadri N. The effect of Allium sativum (Garlic) extract on infectious bronchitis virus in specific pathogen free embryonic eggs. Avicenna J Phytomed. 2016 Aug;6(4):458–267.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Lauren Young

Doctor of Medicine - MD, Medical University of Sofia, Bulgaria

Lauren is a newly qualified doctor, who recently returned to the UK to pursue a career as a GP. Her passions lie in public health, medical education and health advocacy. An avid reader, Lauren has found great joy in combining her love of medicine and the written word in writing health articles for Klarity.

Leave a Reply

Your email address will not be published. Required fields are marked *

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818