A lung infection occurs when a dangerous microbe, such as a bacterium or a virus, gets into the lungs and causes damage. The symptoms depend on the type of infection but may include shortness of breath, coughing, and fever.

Although most types of lung infection are treatable and most people recover, these infections are also very dangerous. This is especially the case for infants, older adults, and people with lung disease or a weak immune system.

Identifying the type of lung infection a person has is important for treating it. Although their symptoms may help with this, a person cannot self-diagnose their own lung infection.

Also, life threatening illnesses such as lung cancer may mimic the symptoms of certain lung infections, so it is important to contact a doctor.

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Pneumonia is a lung infection that causes inflammation in the lungs. It is one of the most common lung infections.

With pneumonia, the alveoli of the lungs, which hold air, swell. This can make it difficult to breathe. In severe cases, it can be fatal.

Bacteria, fungi, and viruses can all cause pneumonia. For example, the flu virus can spread deep into the lungs, causing pneumonia. The bacterium Streptococcus pneumoniae can cause bacterial pneumococcal pneumonia.

COVID-19, which caused the worldwide coronavirus pandemic, is a respiratory disease that causes pneumonia. Severe COVID-19 can cause life threatening pneumonia that leads to organ failure, blood clots, and other health issues.

Some signs and symptoms of pneumonia include:

  • shortness of breath
  • difficulty breathing
  • confusion
  • weakness
  • fever
  • chest pain
  • low blood oxygen levels

Treatment for pneumonia depends on the cause. For example, bacterial pneumonia may respond to antibiotics. Treatment for viral pneumonia is supportive, which means that a doctor will monitor a person and treat their symptoms until their body clears the infection.

Having severe pneumonia may mean that a person has to stay in the hospital or receive oxygen treatment using a mask or ventilator.

Vaccines can prevent some forms of pneumonia, such as pneumococcal pneumonia. They may also reduce the risk of certain types of pneumonia. The flu shot, for example, reduces the risk of the flu and of the pneumonia that it can cause.

A contagious bacterium called Mycobacterium tuberculosis causes tuberculosis (TB).

In some people, TB bacteria live in the body without causing illness. However, in many cases, TB affects the lungs and may also affect other areas of the body.

Some symptoms of TB include:

  • a cough that lasts for longer than 3 weeks
  • coughing up blood
  • chest pain
  • weakness
  • fever or chills

If TB spreads to other areas of the body, it may cause additional symptoms.

The earlier a person seeks treatment for TB, the less likely they are to spread the disease to others or to experience serious complications from it.

Antibiotics can clear the infection. If a person has serious complications, however, they might need other forms of treatment, such as oxygen or intravenous fluids.

Influenza is a respiratory tract infection that affects both the upper airway, including the throat and the nose, and the lungs. Severe cases of influenza can inflame and damage the air sacs of the lungs, causing pneumonia and making it difficult to breathe.

Although the flu usually goes away on its own, people with a weak immune system, infants, young children, and older adults are more likely to experience severe breathing issues. In a newborn, the flu can quickly cause a medical emergency.

Some symptoms of the flu include:

  • severe cold-like symptoms that appear suddenly
  • high fever
  • intense fatigue
  • headache
  • muscle ache
  • vomiting
  • diarrhea

Most people do not need flu treatment. However, a doctor can prescribe anti-flu medications such as Tamiflu within the first few days of symptoms. This can help the flu go away faster and may reduce the risk of complications such as pneumonia.

People with the flu should also:

  • Rest as much as possible.
  • Drink plenty of fluids.
  • Take medications to manage symptoms such as fever.

Antibiotics will not treat the flu. However, some people develop secondary infections, such as ear infections. They should contact a doctor if they experience any new or worsening symptoms to see if antibiotics might be appropriate.

Bronchitis is an infection of the bronchial tubes, which help the lungs take in oxygen. Like pneumonia, the infection can be either viral or bacterial.

In some cases, a person develops bronchitis after having another infection, such as the flu or common cold.

Some symptoms of bronchitis include:

  • wheezing or coughing
  • coughing for several weeks after a cold
  • chest pain
  • fever
  • fatigue

Bronchitis can also manifest as a chronic problem. Chronic bronchitis, however, is not an infection.

Treatment depends on a person’s symptoms and whether their bronchitis is viral or bacterial. Antibiotics will treat only bacterial bronchitis. However, healthy adults may not need antibiotics even when the infection is bacterial.

Viral bronchitis usually goes away on its own. A person may need cough medications or, in more serious cases, steroids. Rarely, a person might need supportive care in the hospital.

Pertussis, or whooping cough, is a highly contagious bacterial infection that is common in infants and young children.

A vaccine can prevent the infection, but decreasing vaccine rates have caused an increase in pertussis cases.

Some symptoms of pertussis include:

  • an intense cough that makes a “whooping” sound
  • long coughing fits
  • difficulty breathing
  • gasping for air

Antibiotics can treat pertussis in many cases. However, the infection can spread quickly in infants and children, so it is important to seek prompt treatment. Even with treatment, some infants still die.

Cough medication does not usually help with symptoms of pertussis.

To prevent pertussis, pregnant people should consider getting the pertussis vaccine. Parents and caregivers should vaccinate their children and consider asking visitors to unvaccinated children to get the pertussis vaccine.

Lung infections can be serious, especially when they spread deep into the lungs or travel to the bloodstream. When the latter happens, they can damage other organs, such as the kidneys or heart.

Although there is no reason to panic, receiving prompt medical care can be life saving. If a person suspects that they have a lung infection, they should call a doctor.