Can a Chest Infection Turn Into Pneumonia

  • 1st Revision: Nabil Jawlakh

Chest infections are frequent, especially in Autumnl and Winter and can affect people of all ages. While the majority of cases are harmless and clear up on their own, pneumonia can develop in a small percentage of people in rare instances.

Chest infections are typically caused by a cold or flu and affect the lungs or the major air passages. Bronchitis and pneumonia are the most common forms of serious chest infection, with viruses typically being the cause in cases of bronchitis and bacteria in cases of pneumonia. As viruses cause the majority of chest infections, it is likely that your immune system will fight off the infection. However, bacterial pneumonia can develop rapidly after a viral cold or flu, usually within 24 to 48 hours or may take several days to manifest.

Common cold symptoms like a clogged or runny nose, sneezing, fever, and cough can be the beginning stages of a chest infection. Even though you may be experiencing fatigue and aches due to a chest infection, these symptoms are typically mild and may not require a visit to the doctor. The infection often clears itself within 7-10 days, but urgent medical attention is necessary if you fear you have a severe infection of the lung (pneumonia).

Symptoms of bronchitis vs. pneumonia

A chest infection affects the lungs' airways (bronchitis) or air sacs (pneumonia). If the infection is in the alveoli, it's pneumonia and if in the bronchi, it's bronchitis.1 Inflammation of the airways causes them to swell and generate more mucus or pus, which blocks airflow and makes it difficult to breathe. These infections are typically transmitted when an infected person coughs or sneezes, releasing fluid droplets containing the virus or bacterium into the air, where they can be inhaled by others.1 A person can also contract an infection by touching a contaminated surface or object.  

Symptoms of chest infection:

  • Cough
  • Fever 
  • Tiredness
  • Headache
  • Shortness of breath
  • Wheezing
  • Production of mucus
  • Tightness or pain in the chest
  • Feeling disorientated
  • Discomfort in the muscles and joints
  • Soreness in the head and neck

These mild symptoms frequently look like a common cold or the flu, but they stick for at least 7-10 days. Cough and mucus may persist for 3 weeks. 

Depending on the infectious agent, the host's immune system, and the severity of the underlying condition, the signs and symptoms could range from quite minor to life-threatening. Mild episodes of chest infections often resolve within a week or two without treatment. However, if you suspect a more serious infection, such as pneumonia or bronchitis, you must visit a doctor.


Pneumonia is an infection that causes inflammation of the air sacs in the lungs. It can be caused by bacteria, viruses, and fungi.2 The air sacs may get filled with fluid, resulting in a cough with phlegm or pus, fever, chills, and trouble breathing. The symptoms of pneumonia can develop suddenly over 24 to 48 hours, or they may come on more slowly over several days.3

Symptoms of pneumonia:3,4

  • a cough that can be dry or produce thick mucus which could be yellow, green, brown, or even blood-tinged (phlegm)
  • chest pain that is greater while inhaling or coughing
  • quick, shallow breathing
  • high body temperature
  • sweating and shivering
  • loss of appetite
  • rapid heartbeat
  • Chills
  • Bluish fingernails

Less common symptoms:

  • bloody cough (haemoptysis)
  • headaches
  • experiencing a sense of disorientation and confusion
  • sore muscles and joints
  • Nausea, vomiting or diarrhoea


Bronchitis is an infection of the major airways of the lungs (bronchi), which causes irritation and inflammation.5 Although a cough from acute bronchitis, often known as a chest cold, might linger for weeks, the condition typically recovers within ten days. However, if your bronchitis symptoms persist for longer than a few weeks, you may have chronic bronchitis and should see a doctor.6 

Symptoms of Acute bronchitis:

  • Cough
  • Difficulty in breathing
  • Wheezing
  • A rattling sensation in the chest
  • Malaise (general state of feeling unwell)
  • Mild fever
  • Slightly irritating and painful tickle in the throat.
  • stiffness or pain in the chest
  • inability to rest properly
  • Chills (uncommon)

Symptoms of Chronic bronchitis:

  • Cough, also known as smoker's cough
  • Sputum-producing cough, which may include blood spots
  • Difficulty breathing that gets worse with even light activity
  • Recurrent respiratory infections
  • Wheezing
  • Fatigue
  • Chest pain
  • Headaches
  • Abnormal breathing noises, including wheezing and crackling
  • Swelling of the feet
  • Bluish lips, fingernails and skin due to low oxygen levels

What causes pneumonia and bronchitis?


Acute bronchitis is frequent and typically results from a viral or bacterial respiratory illness like the common cold. Chronic bronchitis, on the other hand, is far more serious and is frequently brought on by smoking and inhaling irritating substances like cigarette smoke, pollution particles, and other dangerous compounds.7


There are over thirty distinct causes of pneumonia, which are categorised according to their origin, i.e; bacterial, viral, fungi and Mycoplasma.4

Bacterial Pneumonia: Pneumococcal infections, caused by the bacteria Streptococcus pneumoniae, is the most common cause of pneumonia. Haemophilus influenzae and Staphylococcus aureus can also cause pneumonia.

Viral pneumonia: Approximately one-third of all pneumonia cases are caused by a respiratory virus, such as influenza (flu).

Mycoplasma: Mycoplasma pneumoniae, the organism responsible for Mycoplasma pneumonia, is neither a bacterium nor a virus yet shares many characteristics with both.

Fungi: Results from a pulmonary fungal infection. It is uncommon compared to other forms of pneumonia.

Aspiration pneumonia: occurs when a person unintentionally breathes in a little amount of fluid, food, or vomit into their lungs. 

Hospital-acquired pneumonia: Patients in the intensive care unit who are dependent on breathing equipment are at a heightened risk for getting ventilator-associated pneumonia.

Coughing and sneezing are the most common modes of transmission for pneumonia and bronchitis. Sneezing and coughing release infectious droplets into the air, where they can be inhaled by anyone nearby. It is also possible to spread the infections by contacting infected surfaces and then touching your mouth or nose.

Who’s at increased risk for pneumonia?

Infections of the lungs are common in those whose immune systems are compromised due to age, poor nutrition, illness, or other factors.2,3

Pneumonia is especially dangerous for :

  • Infants or young children
  • Elderly
  • People with chronic diseases such as asthma, chronic obstructive pulmonary disease (COPD) or heart disease
  • Weakened immune system: people with AIDS/HIV, organ transplant, receiving chemotherapy or long-term steroids
  • Smokers: The natural defences of the body against pneumonia is compromised by smoking
  • Pregnant women
  • Hospitalized patients 


  • Vaccination: Some strains of the flu and pneumonia can be prevented using vaccines. Doctors prescribe a separate vaccine for children under the age of 2 and those between the ages of 2 and 5 who are at increased risk for pneumococcal illness. Additionally, doctors prescribe flu vaccinations for children older than 6 months. Vaccination should also be administered to children who visit child-care centres.
  • Good hygiene: Keep your hands clean by washing them frequently or using an alcohol-based hand sanitizer.
  • Maintain a healthy immune system by taking plenty of rest, working out regularly, and eating healthily 
  • When you cough or sneeze, use a handkerchief or tissue to cover your mouth and nose
  • Throw the used tissue: used tissues can harbour germs for several hours after they are removed from the nose or mouth


  • Chest X-ray: This examination produces images of interior tissues, bones, and organs, such as the lungs
  • Blood tests: This test can be performed to determine if an infection has progressed to the bloodstream (blood cultures)
  • Sputum culture: This test uses lung and mouth coughed-up material to detect lung infections.
  • Pulse oximetry: It measures blood oxygen
  • Chest CT scan:  A CT scan provides bone, muscle, fat, and organ pictures
  • Bronchoscopy: This is a direct evaluation of the bronchi (the main airways of the lungs) utilising a flexible tube (called a bronchoscope). It helps identify lung issues, assess obstructions, and take tissue/fluid samples for testing
  • Pleural fluid culture: pleural fluid is collected from the lung-chest wall space to identify the pneumonia-causing bacteria


In most cases, mild pneumonia can be managed at home by:3,4

  • Getting adequate rest
  • Taking antibiotics
  • Drinking lots of fluid

You should respond well to treatment and quickly recover if you do not have any other health concerns, though your cough may linger for some time. Pneumonia can be very dangerous for those who are already vulnerable. This is because it is associated with a high risk of complications, some of which can prove fatal depending on the patient's age and state of health.

When to see a doctor?

Consult a physician if you have:3

  • difficulty breathing
  • chest pain
  • a persistent fever of 102 degrees Fahrenheit (39 degrees Celsius) or higher 
  • a chronic cough, especially if pus is coughed up 
  • blood while coughing
  • possess blue lips or blue skin
  • Feel chilly and sweaty
  • weaken to the point of collapsing
  • no longer urinate or urinate far less than normal

It is crucial that people in high-risk categories consult a doctor immediately after showing symptoms.


A cold or flu virus is usually the reason behind a chest infection, but in rare situations, the illness can progress into pneumonia or bronchitis. Pneumonia is an infection of the lungs that can be caused by bacteria, viruses, or fungus and can affect any age group. The most typical sign of pneumonia is a cough that brings up green, yellow, or red mucus along with fever, chills, shortness of breath, weakness, and excessive fatigue. Pneumonia can be treated with antibiotics and taking care of your health. In most cases, medical care is unnecessary because the infection will resolve on its own. Pain relievers, cough suppressants, and fever reducers may be recommended, along with a healthy diet, plenty of fluids, rest, oxygen treatment, and other similar measures. Treatment for pneumonia usually results in a full recovery, although the disease can lead to significant complications in some patients. In extreme cases, it can be fatal. 

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.

Avantika Pandey

General Dentist • Public Health Specialist, University of York, UK

I am a healthcare researcher with a background in dentistry who is presently pursuing a Master of Public Health at the University of York, UK. Prior three years' experience collaborating with medical teams and health care professionals to deliver medical treatment and patient care in clinics and hospitals.
I am a member of The Global Mental Health and Cultural Psychiatry Research Group, which promotes mental health care in LMIC. I am also working under the IMPACT program under University of York for mental health care in LMIC.

Leave a Reply

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