7 Signs of Pneumonia (Mild to Severe Lung Infection)

With air flowing in and out of the airways and lungs on a constant basis, a range of different substances and germs in the environment can also enter to irritate, infect and damage the respiratory organs. This can lead to various respiratory diseases that affect the airway and/or lungs. Once such disease is pneumonia. It is an infection of the lung tissue and can range from mild to severe. Sometimes pneumonia can even be life threatening.

How do the lungs get infected?

Viruses, bacteria and fungi are constantly entering and exiting the airways. These germs (also referred to as microbes, microorganisms or infectious agents) are widespread in the environmental air. Some are harmless to humans and the airways or lungs specifically. Others can reach the lungs and cause an infection. However, not every person exposed to these infectious agents will develop an infection.

The respiratory system has various mechanisms to prevent infectious agents from reaching he delicate lung tissue. This includes filtering and trapping dust particles and infectious agents. From the hair in the nose, to the mucus and tiny hair cells lining the bronchi, the respiratory tract is usually able to prevent these infectious agents from reaching the lungs. Even at the lungs, a strong immune defense can neutralize these agents before it causes an infection.

Read more on what is pneumonia.

If a virulent microbe can reach the lungs and is not neutralized by the immune system, then it can lead to an infection of the lungs, which is known as pneumonia. These germs can then damage the cells of the lung or enter cells, replicate within it and destroy the cells. People with a weakened immune system, very young and very old people and those with pre-existing lung diseases are at a greater risk of developing pneumonia.

Less commonly, germs like bacteria can travel through the bloodstream from another part of the body to then infect the lungs. The germs that cause pneumonia are easily spread from one person to another through droplets. These infective droplets are airborne when a person coughs. It can then enter another person’s airway. Although the pneumonia germs can be acquired anywhere, there is a particular risk within hospitals and health care facilities.

How To Spot Pneumonia

Respiratory tract infections are more common than pneumonia and affects most people several times in life. It can involve the upper respiratory tract or lower respiratory tract infections. The symptoms often overlap with pneumonia. Therefore it is not uncommon for pneumonia to initially be mistaken for a lower respiratory tract infection. However, in most cases pneumonia causes more severe symptoms than a respiratory tract or airway infection.

Always seek medical attention immediately once pneumonia is suspected. Symptoms like bloody sputum, difficult breathing and bluish tinge of the skin requires emergency medical treatment. Some types of pneumonia can progress rapidly and without prompt treatment, it can lead to death.


This is one of the common symptoms of pneumonia. It is usually a productive coughing, meaning that mucus and other secretions produced lower down the airways and lungs can be passed out as sputum. This is also sometimes referred to as a wet cough and the sputum may vary from clear and white to brown and even yellow. In some severe forms of pneumonia, there may be coughing up of blood which is known as hemoptysis.

Read more on pneumonia cough.


Clear, brown to yellow and bloody sputum are not the only colors that may be observed in pneumonia. Green sputum is more often seen with Haemophilus, Pseudomonas and pneumococcal species of bacteria, while rust-colored sputum is more commonly observed with a Streptococcus pneumoniae infection. Similarly there may be variations with the taste and odor of the sputum. Foul-smelling and foul-tasting sputum is often associated with anaerobic bacteria.

Shortness of Breath

There are varying degrees of breathing problems with pneumonia. In very mild cases there may sometimes be no noticeable difficulty with breathing. However, in most cases there is shortness of breath. It may be more obvious during physical activity or with certain positions, including when lying flat. In severe pneumonia, there may be severe difficulty with breathing with significantly low oxygen levels in the blood.

Chest Pain

Chest pain is another common symptom of pneumonia. It occurs due to the inflammation of the lung tissue but also with coughing and labored breathing which strains the chest wall muscles. The degree of chest pain can vary depending on the severity of pneumonia. Usually the pain is worse when coughing or breathing, particularly when inhaling. There may also be abdominal pain preset, especially with severe coughing.

Abnormal Sounds

In pneumonia the breathing rate may be higher than normal (above 18 breaths per minute) which is known as tachypnea. However, the breath sounds are softer (lower in volume) than would normally be expected. In addition there may be other abnormal breathing sounds such as wheezing, rales or rhonchi. This may sound like a whistling, rattling or crackling sound when inhaling, exhaling or both.


A fever is another common symptom of penumonia. The body temperature is raised above 38°C (100.4°F) and may be accompanied by chills and sweating. While a fever is not unexpected in a severe infection such as pneumonia, the reverse may sometimes occur. The elderly may experience a lower than normal body temperature (hypothermia). Temperatures may be recorded below 35°C (95°F).


Fatigue is a common symptom in most infectious diseases. It may be worse when these diseases affect vital organs like the lungs. In pneumonia, the lung function is compromised and the ability to oxygenate the blood and expel carbon dioxide from the body. Sufficient oxygen is necessary for energy production and when oxygen levels are low then symptoms like fatigue become prominent. It is worsened with physical activity.

Other Signs and Symptoms

The other signs and symptom of pneumonia may include:

  • Abnormal heart rate, usually faster (tachycardia) but sometimes slower (bradycardia).
  • Nausea and vomiting
  • Diarrhea
  • Muscle pain
  • Headaches
  • Cyanosis (bluish discoloration) in severe cases, usually of the lips and tongue.
  • Altered mental status, such as confusion, usually in older people.









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