What Is A Chest Infection?


At a glance:

  • Chest infections are any infection that affect the breathing passages and lungs
  • The two most common forms of chest infection are bronchitis and pneumonia
  • Bronchitis is an infection of the bronchi, the large airways that deliver air to the lungs
  • Pneumonia is an infection of the alveoli, the small air sacs that transfer oxygen to the bloodstream
  • Viruses and bacteria are the most common causes of chest infections, but in rare cases they can also be caused by fungus
  • How an infection is treated depends on the source of the infection 

What is a Chest Infection?

A chest infection is any infection, typically bacterial or viral, that affects your breathing passages and lungs. The two most common forms of chest infection will affect the bronchi, large air passages that enter the lungs (bronchitis), or affect the alveoli, the small air sacs in the lungs ( pneumonia ).

When they are infected, the airways or air sacs become inflamed, constricting breathing. An infection may also lead to the affected airways producing mucus or pus, leading to further breathing complications. 

Chest infections may affect people of any age, but young children and babies, pregnant women, smokers, people with underlying health conditions or compromised immune systems, and the elderly are more at risk than any other group. Worldwide, viral pneumonia is one of the leading causes of death in children under 5 years of age.

Symptoms of a Chest Infection

Chest infection symptoms vary depending on the parts of the lung affected, and the intensity of symptoms may vary due to the underlying cause. Pneumonia symptoms include:

Symptoms of bronchitis include:

As many of the symptoms of the two most common chest infections, seeing a doctor for a proper diagnosis is recommended.

Both bronchitis and pneumonia are typically mild, but people with high risk factors may be susceptible to more serious cases. 


If you, or a loved one is experiencing symptoms of chest infection, it’s important to find out the underlying cause so you can undergo the correct treatment, so schedule a consultation with a doctor or make time to speak to the Virtual Respiratory Clinic . The fastest and easiest way to search for and book healthcare appointments online is through MyHealth1st.


What Causes a Chest Infection?

Chest infections are typically caused by a viral or bacterial infection, but in rare cases they may also be caused by fungal infections. The diagnosis of what kind of chest infection has been contracted depends on the location of the infection.

Acute (short lasting) bronchitis is typically caused by a viral infection, whereas pneumonia can be caused by viral or bacterial infections equally.

Viruses that may lead to a lung infection include:

  1. Cold - this is a general term. There are over 250 identified viruses that may cause a common cold
  2. Influenza A and B
  3. Parainfluenza - not related to influenza but rather a separate virus referred to as Human Parainfluenza Virus (HIV)
  4. Adenovirus - a family of viruses that may produce cold-like symptoms as well as conjunctivitis
  5. Respiratory syncytial virus (RSV) - the leading cause of bronchiolitis (childhood bronchitis)
  6. Coronavirus - the coronavirus family may cause cold and flu like symptoms leading to further infection. This family includes Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and COVID-19

Bacterial that may cause a chest infection include:

Streptococcus Pneumoniae - the most common cause of Community Acquired Pneumonia (CAP). Unfortunately a number of strains of the bacteria have developed resistance to antibodies

Haemophilus Influenzae - another common cause of bacterial CAP. Haemophilus influenzae can also cause epiglottitis (inflammation of the epiglottis), meningitis (inflammation of the brain lining and stem), osteomyelitis (infection of the bones and joints) and cellulitis (infection of the tissue between the skin and muscle)

Pseudomonas Aeruginosa - one of the bacteria responsible for most cases of Hospital Acquired Pneumonia (HAP).

Staphylococcus Aureus - another common cause of HAP

Moraxella Catarrhalis - a fairly common cause of ear or sinus infections in children. Typically only affects adults with compromised immune systems of other lung conditions such as COPD.

Streptococcus Pyogenes - also known as Group A Streptococcus (GAS)

Neisseria Meningitidis - also known as meningococcus, Neisseria Meningitidis is typically associated with meningococcal disease but may also cause pneumonia

Klebsiella Pneumoniae - these bacteria typically live in your intestine and bowel but if ther spread to other areas of the body such as the lungs can lead to severe infection

Mycoplasma Pneumoniae - this small bacteria is responsible for around one fifth of bacterial respiratory infections. Pneumonia caused by Mycoplasma pneumoniae is sometimes referred to as “walking pneumonia” as the symptoms are typically quite mild

Fungal chest infections are relatively rare and typically only affect people with depressed immune systems, such as people taking immunosuppressants, or with conditions such as cancer or HIV/AIDS. Possible causes of fungal chest infections include:

Aspergillus - this fungus found on rotting vegetation. Infection from aspergillus may cause pneumonia-like symptoms but is typically referred to as aspergillosis

Histoplasma Capsulatum - infection from this soil-based fungus is referred to as histoplasmosis

Sporothrix Schenckii - if inhaled, this soil-based fungus may cause a pneumonia-like disease called sporotrichosis, sometimes known as “Rose Gardener’s Disease” due to it sometimes living on rose buds

Cryptococcus Neoformans - this yeast-like fungus may cause pneumonia-like symptoms if inhaled, but typically only in people with weakened immune systems, such as those with advanced stage HIV/AIDs

Treatment for a Chest Infection

Discovering the cause of your chest infection is key to successfully treating it. Viral infections may typically be treated with home care and rest. Bacterial infections may require a prescription for medication and fungal infections invariably require specialised treatment.

While viral pneumonia can be very dangerous to at-risk groups, for the most part viral chest infections may be treated with home care, such as:

  • Get plenty of rest - elevating pillows at high may help alleviate symptoms
  • Stay well hydrated - drinking plenty of fluids may help loosen phlegm and mucus making it easier to expel
  • Use over the counter painkillers - headaches fever and muscle/joint aches may be treated with painkillers such as ibuprofen or paracetamol
  • Quit smoking - if you are a smoker, stopping smoking may speed recovery and reduce the severity of symptoms
  • Inhaling steam - this may help to relieve coughs and loosen up the chest 

Bacterial and fungal infections may require home care, but will most likely also require a course of medication. In the case of bacterial infections, this will typically be a course of prescribed antibiotics. For mild and moderate cases, a course of tablets will suffice, but in serious cases intravenous antibiotics may be necessary. Similarly, fungal infections require treatment with a course of antifungal medications.

Although there is no way to immunise yourself against a chest infection, there are a few ways in which you can reduce the risk of contracting one, including:

  • Vaccinations - keeping up to date with flu shots and other vaccinations may reduce your risk of contracting a viral chest infection
  • Maintain hand hygiene - washing your hands thoroughly and often may reduce the chance of transferring bacteria, fungus or a virus from a surface to one of your mucus membranes
  • Quit smoking - smoking increases the risk of lung related sickness

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