Lower respiratory tract infections are any infections in the lungs or below the voice box. These include pneumonia, bronchitis, and chest infections.

When to seek emergency care

According to the Centers for Disease Control and Prevention, adults should seek emergency care if they experience the following emergency warning signs:

Parents and caregivers should seek emergency care if a child experiences the following emergency warning signs:

  • fast breathing
  • difficulty breathing
  • blue or gray lips or face
  • chest pain
  • ribs that pull in as the child breathes
  • severe muscle pain
  • signs of dehydration, including:
    • dry mouth
    • no urination for 8 hours
    • no tears when the child cries
  • seizures
  • a lack of alertness
  • difficulty interacting
  • fever over 104 degrees Fareinheit
  • fever or cough that improves but then comes back or worsens

A lower respiratory tract infection can affect the airways, such as with bronchitis, or the air sacs at the end of the airways.

Although most lower respiratory tract infections resolve without medical intervention, they can be more severe than upper respiratory tract infections and can last longer. Complications can be severe, so people must be aware of emergency warning signs.

Symptoms of lower respiratory tract infections vary and depend on the severity of the infection. Typically, respiratory tract infections cause symptoms such as:

  • cough, that might include mucus
  • shortness of breath, tight chest, or wheezing
  • sneezing
  • sore throat
  • blocked nose
  • change or loss of taste and smell
  • headache

A person may also experience:

  • muscle aches
  • fever
  • feeling generally unwell (malaise)
  • appetite loss
  • nausea and vomiting, in some cases

According to the United Kingdom’s National Health Service (NHS), lower respiratory tract infections affect the airways and lungs, while upper respiratory tract infections affect the sinuses and throat.

Lower respiratory infections tend to be more serious and can last longer than upper respiratory infections.

Examples of lower respiratory tract infections include:

  • bronchitis
  • pneumonia
  • chest infections
  • bronchiolitis
  • tuberculosis

Examples of upper respiratory infections include:

  • cold
  • tonsilitis
  • sinusitis
  • larnygitis

Illnesses such as COVID-19 and the flu can affect both the upper and lower respiratory tracts.

Infections in the lower respiratory tract are primarily the result of:

  • viruses, which can cause:
    • influenza
    • COVID-19
    • bronchitis
    • bronchiolitis
  • bacteria, such as Streptococcus or Staphylococcus aureus
  • fungal infections
  • mycoplasma, which are neither viruses nor bacteria, but are small organisms with characteristics of both

In some cases, substances from the environment, such as air pollution, increase the risk and severity of respiratory infections. Other examples include:

  • tobacco smoke
  • dust
  • chemicals
  • vapors and fumes
  • allergens
  • air pollution

A doctor usually diagnoses a lower respiratory infection based on a person’s symptoms.

They will also perform a physical exam. During the exam, the doctor will listen to the person’s chest and breathing through a stethoscope.

The doctor may order tests to help diagnose the problem, such as:

  • pulse oximetry to find how much oxygen is in the blood
  • chest X-rays to check for pneumonia
  • blood tests to check for bacteria and viruses
  • mucus samples to look for bacteria and viruses

Recovery time for a lower respiratory tract infection varies from person to person. Most respiratory infections go away on their own within 1 to 2 weeks, but for some people, recovery can take a month or more.

During this time, a person can try the following:

  • Drink plenty of fluids.
  • Get plenty of rest, if possible.
  • Take over-the-counter medications for a cough or fever.
  • Sleep with extra pillows to raise the head, making it easier to breathe.

Depending on the cause and severity, a person may require antibiotic or antiviral treatment. In some more severe cases, a person may need to visit the hospital to receive IV fluids, antibiotics, or breathing support.

Very young children and older adults may need closer monitoring and additional treatment options if they are at an increased risk of severe infection.

A person can take many steps to prevent getting a lower respiratory tract infection, including:

  • washing their hands frequently
  • avoiding touching the face with unwashed hands
  • staying away from people with respiratory symptoms, if possible
  • cleaning and disinfecting surfaces regularly
  • getting vaccines, such as the pneumococcal vaccine and MMR vaccine
  • getting a flu shot every year
  • avoiding known irritants, such as chemicals, fumes, and tobacco

Most healthy people make a full recovery from uncomplicated lower respiratory tract infections.

Most lower respiratory tract infections are uncomplicated, and people make a full recovery. However, when complications occur, they can be very serious.

Complications of lower respiratory tract infections can include:

  • respiratory failure
  • acute respiratory distress syndrome (ARDS), which is a severe form of respiratory failure
  • sepsis, which is a blood infection that can lead to organ shutdown
  • lung abscesses

Risk factors that make a person more likely to develop severe lower respiratory tract infections include:

  • having a weakened immune system
  • being over 65 years old
  • being a young child
  • being pregnant

A person should contact a doctor if they experience the following:

  • feeling very unwell
  • worsening symptoms
  • coughing up blood or noticing blood-stained mucus
  • a cough that lasts over 3 weeks

People should also contact a doctor if they develop a lower respiratory tract infection and they:

  • are pregnant
  • are over 65
  • have a weakened immune system
  • are undergoing chemotherapy
  • have a long-term health condition affecting the heart, lungs, or kidneys

Lower respiratory tract infections affect the airways and the lungs. Examples include pneumonia, bronchitis, chest infections, and bronchiolitis. COVID-19 and the flu can affect both the upper and lower respiratory tracts.

There are many possible symptoms of a lower respiratory tract infection, including cough, shortness of breath, tight chest, wheezing, and loss of taste and smell. A person may also experience fever and muscle aches.

Most people recover from a lower respiratory tract infection over the course of a couple of weeks. Getting plenty of rest, keeping well-hydrated, and taking OTC medications can help ease symptoms during this time.

Lower respiratory tract infections can be severe and cause complications. It is important for people to know the emergency warning signs so they can receive quick medical attention.