What to Know About Lung Infections

Many people are familiar with the symptoms of lung infections, such as an annoying cough and fever, but there are many different types of these infections. Lung infections can be caused by different microorganisms (viruses, bacteria, or fungi) and affect different regions of the lungs and airways.

Learn about the risk factors for lung infections, the different types that occur, and how they are treated.

lung infection

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What Is a Lung Infection?

A lung infection is a condition in which a disease-causing microorganism causes damage and inflammation—due to the gathering of immune cells—in the airways or tissues of the lungs.

Lung infections may be caused by viruses, bacteria, fungi, or rarely in the United States, parasites. In some cases, more than one type of microorganism is responsible. For example, viral bronchitis may lead to bacterial pneumonia.

Lung infections can be mild or severe and can affect people of any age—though some infections are much more common at certain ages. They may affect airways of any size (bronchi, bronchioles, alveoli) or the tissues that surround the airways of the lungs.

Common Symptoms

There are a number of symptoms commonly seen with lung infections, and these may occur no matter what type of infection is present. There are also symptoms that are less common but no less important.

  • Cough: A cough may be dry or “wet” (productive of mucus) and may be mild or severe.
  • Mucus production: Mucus may be clear, yellow, green, brown, or rust colored and may have no odor or a foul odor.
  • Wheezing: Wheezing most commonly occurs with expiration (breathing out), but may occur with both expiration and inspiration in some cases. A different sound, “stridor,” is usually higher pitched than wheezing and occurs primarily with inspiration. Stridor is commonly seen with infections in the airways above the lungs, such as the windpipe (trachea) with epiglottitis.
  • Fever: Temperature may be low-grade (less than 100 degrees F), high, or very high.
  • Chills or rigors (severe chills may be referred to as shaking chills): These may occur as a fever goes up, and sometimes sweats (drenching sweats) may occur as a fever goes down.
  • Upper respiratory symptoms: Nasal congestion, sore throat, hoarseness, laryngitis, and headaches commonly occur, especially with viral infections.

Other common symptoms may include muscle aches (myalgia), joint aches (arthralgia), loss of appetite, fatigue, nausea, and vomiting or diarrhea.

Less commonly, lung infections may lead to symptoms such as:

  • Coughing up blood (hemoptysis)
  • Looking unwell
  • Shortness of breath (dyspnea) or labored breathing
  • Rapid respiratory rate (tachypnea): Normal respiratory rates differ by age
  • Chest pain, which can be aching or sharp with a deep breath (pleuritic chest pain)
  • Cyanosis (a bluish tinge to lips, fingers, and toes)
  • Crackling or crunching sounds with breathing
  • Confusion or falls (in the elderly)
  • Lethargy (in infants)
  • A change in fingers (and sometimes toes) such that they take on the appearance of upside-down spoons (clubbing)

When to Call a Doctor

Certainly, it’s important to call your doctor if you have any concerns at all. After all, you know your body and what is normal or not for you. But there are some symptoms that warrant a prompt call.

When to Call a Doctor

Call a healthcare provider if you experience any of the following:

  • High fever (over 100.5 to 101 degrees F)
  • Symptoms that persist beyond two weeks (a cough can sometimes last longer)
  • Coughing up blood or rust-colored sputum
  • Shortness of breath, especially if it occurs at rest
  • Chest pain (other than a mild ache related to coughing)
  • Rapid respiratory rate
  • Fast pulse (a heart rate greater than 100 beats per minute) or palpitations
  • Lightheadedness
  • Confusion or falls (elderly)
  • Poor feeding or lethargy (infants)
  • Signs of dehydration such as thirst, few wet diapers, or failure to cry tears in infants
  • Nausea and vomiting

Types of Lung Infections

The many different types of lung infections can be distinguished by how they affect the lungs and airways. While some organisms are more likely to cause a certain type of infection, there can be significant overlap. For example, some viruses may cause both bronchitis and pneumonia.

Some of the more common lung infections are discussed here.

Bronchitis

Bronchitis is an infection of the large airways (the bronchi) that travel between the trachea (windpipe) and the smaller airways. It is most commonly caused by a viral infection, though in 1% to 10% of cases, a bacterial infection is responsible.

Bronchiolitis

Bronchiolitis is an infection that affects the smaller airways (bronchioles) between the larger bronchi, and the tiny alveoli where the exchange of oxygen and carbon dioxide takes place. Most common in children under two years old, it is the leading cause of hospitalizations of infants during the first year of life. That said, most children do not require hospitalization for the infection.

After recovery, it appears that children who have had bronchiolitis have an increased risk of developing recurrent wheezing/asthma during childhood and possibly beyond.

Common Cold

Most people are familiar with the common cold, as these infections are responsible for 60% to 80% of school absences in children and 30% to 50% of time lost from work for adults. During the first six years of life, children average six to eight colds per year, dropping later down to three to four colds per year for adults.

Coronavirus

Most people are familiar with coronaviruses due to the COVID-19 pandemic, but there are actually seven (possibly eight) of these infections.

Enterovirus

Non-polio enteroviruses are a group of several common viruses that sometimes cause lung infections. This class of viruses is also responsible for hand, foot, and mouth disease (enterovirus A71), as well as some severe infections such as myocarditis (inflammation of the heart), meningitis, encephalitis, and more.

Infections often begin with cold-like symptoms such as a fever, runny nose, body aches, and often a rash.

Croup

Croup is an infection that involves structures above the lungs (the larynx and trachea) but can also involve the bronchi. It is caused most often by a number of viruses, including common cold viruses and respiratory syncytial virus, but occasionally due to a bacterial infection.

Symptoms often begin with a low-grade fever and runny nose, followed by the characteristic barking cough which worsens at night.

Influenza

The seasonal flu is one of the best-known lung infections and has affected most people at one time. Both influenza A and influenza B viruses are spread through droplets when a person coughs, sneezes, or even talks, making the disease very contagious.

Symptoms may include:

  • Fever and chills
  • Sore throat
  • Nasal congestion or a runny nose
  • Body aches
  • Headaches
  • Fatigue
  • A mild cough

Whooping Cough (Pertussis)

While many people may think of whooping cough (pertussis) as a vaccine-preventable lung infection of the past, it is still present, and healthcare providers need to be alert for the disease when people present with suspicious symptoms.

The disease can range from mild to severe, but is usually of greatest concern for infants and young children (around 50% of babies under 12 months of age require hospitalization). Among babies and young children, almost a fourth will develop pneumonia. Less commonly (0.3%), complications such as encephalitis may occur.

Consider Pertussis

Since prompt treatment can reduce the severity of cough with whooping cough, being aware that the infection may occur even in people who have received all their vaccines and visiting a healthcare provider if you have symptoms of concern are paramount.

Tuberculosis

A disease that is more common in developing regions of the world, Mycobacteria tuberculosis—the bacteria that causes tuberculosis (TB)—leads to around 8,900 active infections in the United States each year. Fortunately, however, the incidence of TB is now the lowest it has been since recording of the disease began in 1953.

Pneumonia

Pneumonia is a lung infection that affects the smallest of airways, the alveoli, where the exchange of oxygen and carbon dioxide takes place. The severity can range from a mild disease that can be treated at home, to life-threatening infections requiring intensive care.

Symptoms of pneumonia can include:

  • A feeling of being very unwell (which can come on quite rapidly)
  • A cough (though the cough with pneumonia can be similar to that with bronchitis)
  • Phlegm production that may be rust colored or contain blood
  • High fever and chills
  • Shortness of breath
  • Chest pain
  • A rapid respiratory rate
  • A rapid pulse

Risk Factors

Risk factors for lung infections can vary based on the particular infection, though there are some common factors that can increase risk for several, if not all of these infections.

Common Risk Factors

Common risk factors include:

  • Smoking or exposure to secondhand smoke
  • Exposure to air pollution or dust at work
  • A history of asthma or allergies
  • Crowded living conditions
  • Winter months in the northern hemisphere
  • Dry mucous membranes
  • Gastroesophageal reflux disease (GERD)
  • Anatomical problems involving the face, head, neck, or airways, including problems such as nasal polyps or a deviated septum
  • Lower socioeconomic status
  • Malnutrition
  • Lack of immunizations (such as pneumococcal vaccines in children or the pneumonia shot in eligible adults)

Risk Factors in Children

Risk factors found primarily in children include:

  • Greater exposure via daycare setting, school, or multiple siblings
  • Being male
  • Prematurity
  • Bottle feeding (instead of breastfeeding)
  • Pacifier use
  • Age (children less than age 6 are more susceptible in general, and bronchiolitis occurs most often in children less than age 2)
  • Children born to mothers who smoked during pregnancy
  • Congenital heart and/or lung diseases

Less Common but Important Risk Factors

Other risk factors for lung infections can include:

  • Swallowing disorders (these can lead to aspiration of the contents of the mouth or stomach)
  • Lung diseases, such as bronchiectasis, emphysema, alpha-1-antitrypsin deficiency, or cystic fibrosis
  • Cancer, especially blood-related cancers such as leukemias and lymphomas
  • Primary immunodeficiency syndromes (There are many of these syndromes, with some, such as selective IgA deficiency, relatively common.)
  • Secondary immunosuppression (from medications, cancer treatment, HIV, etc.)
  • Absence of a spleen (either due to surgical removal or conditions such as hereditary spherocytosis)
  • Anatomical problems involving the face, head, neck, or airways

Treatment

The treatment for a lung infection will vary depending on the particular infection as well as the organism causing the infection, but some therapies may be used for most infections.

Home Remedies

Home remedies include:

  • Taking Tylenol (acetaminophen) or ibuprofen
  • Getting adequate rest, and drinking plenty of fluids
  • Using a cool-mist vaporizer

While some people choose to use cough/cold preparations for symptoms, a teaspoon of honey may be the safest alternative and also appears to be more effective according to a recent study.

Prescriptions/Hospital Treatments

While most viral infections will need to run their course, treatment may be helpful in some settings. Otherwise, bacterial infections will usually require antibiotics (see below).

For people who develop narrowing of the airways with a lung infection (reactive airway disease), inhalers that open the airways, as well as corticosteroids, may be recommended.

In people who develop low oxygen levels (hypoxia) due to their lung infection, oxygen therapy may be needed. With severe illness, assisted breathing or mechanical ventilation may be required.

Viral Infections

With viral infections, supportive measures to improve comfort are the major treatment. When influenza A is detected early, treatment with Tamiflu (oseltamivir) may reduce the severity and duration of the infection. For very-high-risk children with bronchiolitis due to RSV, a monoclonal antibody treatment may be considered.

With the current pandemic, a number of COVID-19 treatments have been tried, with some (such as steroids) useful in reducing the severity of the disease.

Bacterial Infections

Antibiotics are the mainstay of treatment for bacterial lung infections, with different antibiotics recommended depending on the particular type of infection and suspected organism. The choice of using oral antibiotics versus intravenous treatment will depend on the severity of the infection.

With pneumonia, it’s important to begin antibiotics as quickly as possible. Antibiotics are selected based on the most likely causes of the infection, but may be changed to a more appropriate antibiotic when cultures and sensitivities are returned.

Fungal and Parasitic Infections

With fungal pneumonia, anti-fungal medications such as Diflucan (fluconazole), Nizoral (ketoconazole), or Ancobon (flucytosine) may be used.

Parasitic infections are treated with anti-parasitic medications depending on the infection.

Complications

Lung infections are important in their own right, but may, in some cases, exacerbate other medical conditions or lead to long-term lung concerns.

Acute

Viral lung infections can trigger an asthma attack in patients with existing asthma.

Lung infections are also a very important cause of COPD exacerbations, and COPD exacerbations can worsen underlying COPD.

Chronic

As noted, bronchiolitis in infants and young children is associated with an increased risk of wheezing and asthma later in childhood.

There is also concern that viral lung infections may play a contributing role in the development of COPD in the future.

A Word From Verywell

Nearly everyone experiences a lung infection from time to time, and it’s helpful to be aware of common symptoms, as well as those that should alert you to call your doctor. Fortunately, at least with bacterial lung infections, these illnesses that often proved fatal in the past are now easily treated with a course of antibiotics.

Still, the old adage that “an ounce of prevention is worth a pound of cure” was never more appropriate than when discussing these infections. Infection precautions (which the general public is now very familiar with), immunization when indicated, prompt medical care if anything seems abnormal, and appropriate treatment remain the most important goals.

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