By Helen Massy 

 Medically reviewed by Sanja Jelic, MD

Bronchiectasis, bronchitis, and pediatric bronchiolitis are all disorders of the airways of the lung. However, they are different conditions. 

Bronchiectasis is a permanent condition in which the airways in the lungs have become widened and scarred.1 The United States has a high prevalence of bronchiectasis compared with countries worldwide.2

Bronchitis includes two types of disorders—acute and chronic bronchitis. Both affect the bronchi and bronchioles (the large and small airways of the lungs).

Acute bronchitis is caused by a viral infection, comes on suddenly, and resolves after approximately 10 days. Chronic bronchitis is a severe and progressive lung disease that predominantly affects adults over the age of 40.3

Pediatric bronchiolitis is inflammation of the bronchioles. It usually affects children under the age of 2. It causes coughing and shortness of breath.4

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There can be similarities in the symptoms of all these conditions. However, they are not the same. Some will resolve, and some are permanent. Therefore, the outlooks and treatments are very different. An accurate diagnosis is needed to confirm any lung concerns so that treatment can be tailored appropriately.

This article will compare the causes, risk factors, symptoms, diagnosis, and treatment of bronchiectasis, acute bronchitis, chronic bronchitis, and bronchiolitis.

Causes

Bronchiectasis Causes

Bronchiectasis is the result of the walls of the airways being damaged. A number of things can cause this irreversible damage, including:

• Cystic fibrosis

• Severe lung infection: Such as pneumonia, tuberculosis, whooping cough, or a fungal infection

• Allergic bronchopulmonary aspergillosis (ABPA): A lung disease caused by an allergic reaction to a common fungus called Aspergillus

• Common variable immune deficiency (CVID): A disorder that impairs the immune system

• HIV and AIDS: A rare cause of bronchiectasis

• Primary ciliary dyskinesia: A disorder of the hair-like cells that line the respiratory tract and sweep away debris and secretions

• Chronic pulmonary aspiration

• Connective tissue disorders: Such as Crohn's disease, rheumatoid arthritis, or Sjögren's syndrome 

• Airway blockage: Such as an inhaled object, growth, or noncancerous tumor1

Chronic Bronchitis Causes

Chronic bronchitis and emphysema are collectively known as chronic obstructive pulmonary disease (COPD). Most people with COPD have elements of both chronic bronchitis and emphysema, although it varies from person to person.5

The leading cause of chronic bronchitis is long-term exposure to breathing in a harmful substance such as cigarette smoke. This causes damage to the airways and the lungs that is irreversible. In the United States, cigarette smoke is the main cause, and COPD affects more than 16 million Americans.5

In addition to cigarette smoke, other substances can also cause chronic bronchitis, often from the workplace. These include substances such as coal dust, cadmium dust and fumes, grain and flour dust, silica dust, welding fumes, and isocyanates.6

Acute Bronchitis Causes

Acute bronchitis is usually caused by an infection or something that has irritated the airways, like smoke or air pollution. The cells that line the bronchi become infected and/or inflamed, which lasts approximately 10 days. Although it can cause a cough and difficulty breathing, it is short-lived and does not cause any permanent damage.

The most common viral infections that cause acute bronchitis (which tend to cause the common cold or flu) include:

• Rhinovirus

• Adenovirus

• Influenza A and B

• Parainfluenza

• Respiratory syncytial virus7

Bacterial infections can also cause acute bronchitis, more commonly in people who have an underlying health problem. These organisms include:

• Mycoplasma pneumoniae

• Streptococcus pneumoniae

• Haemophilus influenzae

• Moraxella catarrhalis

• Bordetella pertussis7

Although the viral or bacterial infection might clear up in seven to 10 days, the cough can last several weeks. Research identifies that in 50% of patients, the cough usually lasts for less than three weeks. In 25% of patients, it lasts for more than one month.7

Bronchiolitis Causes

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. The virus causes the bronchioles to become infected and inflamed. This narrows the airways, reducing the amount of air entering the lungs and therefore making it difficult to breathe.

Although RSV is the most common cause of bronchiolitis, other viruses known to cause the condition include:8

• Human rhinovirus

• Coronavirus

• Human metapneumovirus

• Adenovirus

• Parainfluenza virus

• Human bocavirus

Bronchiolitis is most common in children under the age of 2 years, affecting up to 30% of all children under age 2. It is the most common cause of hospital admissions for infants under age 1.9

Diagnosis

To diagnose these conditions:

• Bronchitis is usually diagnosed by physical examination and a chest X-ray. 

• Bronchiectasis is usually diagnosed by using a high-resolution computed tomography (CT) scan of the chest. 

• Bronchiolitis is typically diagnosed with a clinical exam.

Risk Factors

Bronchiectasis Risk Factors

Bronchiectasis can affect anyone at any age. You are at risk if you have a chronic condition that damages the lungs or have a condition that causes multiple lung infections. 

Conditions that increase your risk of developing bronchiectasis include cystic fibrosis, ABPA, CVID, primary ciliary dyskinesia, and certain connective tissue disorders.

In adults, it is more commonly seen in women; however, in children, it is more prevalent in boys.1 

Chronic Bronchitis Risk Factors

The most significant risk factor for developing chronic bronchitis is smoking. Exposure to air pollutants can also play a role. However, this is seen more in developing countries. Occupational exposure to harmful substances, such as through coal mining, is also a risk factor for developing chronic bronchitis. 

Another risk factor is genetics. You are more likely to develop chronic bronchitis if you smoke and you have a relative with the condition.5

Acute Bronchitis Risk Factors

Risk factors for developing acute bronchitis include:

• A history of smoking

• Living in a polluted place10

• Overcrowding

• A history of asthma

Some people find that allergens like pollens, perfumes, and vapors can also trigger acute bronchitis.

Bronchiolitis Risk Factors

Risk factors for bronchiolitis include:

• Parents who smoke

• Low birth weight (premature infants)

• Babies aged less than 5 months

• Low socioeconomic status

• Airway abnormalities

• Congenital immune deficiency disorders

• Crowded living environment

• Chronic lung disease11

Some children who are at high risk of developing severe bronchiolitis may be offered a monoclonal antibody injection. Synagis (palivizumab) and Beyfortus (nirsevimab) are monoclonal antibodies that can help protect certain infants and children 24 months and younger who are at high risk of serious complications from RSV during their RSV season.

Synagis and Beyfortus are not vaccines and cannot cure or treat a child diagnosed with RSV. If your child is at very high risk for RSV infection, your pediatrician may discuss these option with you.

Symptoms

Bronchiectasis Symptoms

Although you may have a condition that causes bronchiectasis, the symptoms may not become apparent for months or years after the damage has begun in the lungs. 

Symptoms include:

• Daily cough

• Daily production of large amounts of yellow/green mucus

• Shortness of breath

• A wheezing or whistling sound when breathing

• Fatigue

• Chest pain

• Clubbing (the flesh becomes thick under toe/fingernails)

• Recurrent lung infections

Although symptoms do not develop right away, they do worsen over time. Symptoms such as shortness of breath and fatigue can significantly affect your quality of life, making activities of daily living difficult.12

Chronic Bronchitis Symptoms

As the name suggests, this is a chronic condition, and the symptoms worsen over time. This makes daily activities increasingly difficult, but treatment can help slow the progression. The predominant symptoms of chronic bronchitis are:

• A persistent cough that does not go away

• Increasing breathlessness

• Frequent chest infections

• Excess mucus production

• Frequent wheezing

• Difficulty taking deep breaths5

Acute Bronchitis Symptoms

Acute bronchitis symptoms often begin similarly to those of a common cold. The illness is short-lived and usually improves over 7 to 10 days, although a cough may persist. The most common symptoms are:

• Low-grade fever

• A runny nose

• Chest congestion

• Breathlessness on exertion

• Wheezing or a whistling sound while breathing

• A cough (may produce yellow or green mucus)

• Fatigue3

Complications

Acute bronchitis is often not a cause for concern, but it may lead to complications such as pneumonia. It can also be confused with other conditions such as asthma.13 Therefore, it is important to see a medical professional to ensure the correct diagnosis and treatment.

Bronchiolitis Symptoms

Bronchiolitis symptoms tend to start like a common cold, with a cough, low-grade fever, and runny nose. However, they then worsen over a few days before reaching the peak and beginning to improve. In most children, bronchiolitis lasts approximately a week to 10 days, and they improve within two to three weeks.

Symptoms include:

• A persistent dry cough (may sound like a rasping cough)

• Wheezing or noisy breathing

• Feeding less

• Having fewer wet diapers

• Vomiting after feeding

• Irritability

• Occasional pauses in breathing4

When to Call a Doctor

Bronchiolitis symptoms can vary from being very mild and manageable at home to acute respiratory failure requiring invasive ventilation.14 If your child shows signs of having trouble breathing or dehydration, consult your doctor immediately. If severe symptoms arise, such as blue lips or skin or respiratory failure, call 911 immediately.

Treatment

Bronchiectasis Treatment

The goal of bronchiectasis treatment is to prevent infections and flare-ups where possible. Therefore, there are several different treatment options and lifestyle changes that can help:

• Antibiotics: These are used to treat infections/flare-ups. Usually oral but may be given intravenously if the infection is severe. 

• Mucolytics: This type of medication is used to help thin mucus to allow it to be coughed up more easily.

• Bronchodilators: The inhaled medications help relax the muscles around your airways.

• Airway clearance devices: These can be used to help break up mucus. Oscillating positive expiratory pressure (PEP) is an example of an airway clearance device. 

• Inhaled corticosteroids: These can be used to treat inflammation in the airways.  

• Manual chest clearance techniques: Postural drainage positions and chest physiotherapy techniques can help clear mucus.

• Lifestyle changes: Helpful changes include stopping smoking or avoiding secondhand smoke, eating a healthy diet, clearing mucus regularly, keeping up to date with vaccinations, avoiding people when they have a cold/flu, and continuing with mucus clearance techniques daily. 

• Oxygen therapy: May be prescribed in severe cases where oxygen levels in the blood are low.1

Chronic Bronchitis Treatment

There is no cure for chronic bronchitis. However, treatments can help slow the progression.

Treatment options include:

• Stopping smoking: This is the most important thing you can do if you have chronic bronchitis. 

• Inhaled medication: Bronchodilators or inhaled corticosteroids can help open your airways and reduce inflammation.

• Pulmonary rehabilitation: This is a specialized program combining exercise and education that helps you to manage your breathing and understand your condition.

• Surgery: A lung transplant can sometimes be an option. Still, only a very small number of people are suitable.

• Dietary changes: A dietitian can advise you on the best things to eat to help you manage your chronic bronchitis.

• Home oxygen therapy: Some people may need to use a portable oxygen tank if their blood oxygen levels are low.5

Acute Bronchitis Treatment

Acute bronchitis is usually a viral infection, and therefore antibiotics are not typically effective. In most cases, acute bronchitis will resolve on its own over time. To help speed up the recovery process, the following care tips are advised:

• Rest.

• Drink plenty of fluids and stay hydrated.

• An over-the-counter cough suppressant or pain reliever may help if required.

• A humidifier or steam can help loosen chest congestion.

Although antibiotics are not usually effective, your doctor may prescribe them if a bacterial infection is suspected.7

Bronchiolitis Treatment

Antibiotics are not effective for bronchiolitis. In mild cases, your child can be cared for at home. To help your child feel comfortable, you can:

• Ensure they stay hydrated by drinking plenty of fluids.

• Help them sit upright if they are eating or are uncomfortable lying down.

• Use saline drops and a nasal bulb to help clear mucus.

• Avoid polluted environments and smoking at home.

• Use over-the-counter fever medication such as Tylenol or Advil if they have a fever.

If you are concerned about your child or they show any signs of difficulty breathing, then call 911. Your child may be admitted to the hospital if they are not getting enough oxygen, not eating, or become dehydrated. Hospital treatments may include oxygen therapy, intravenous fluids, and feeding support if required.

Summary

Bronchiectasis is a permanent widening and scarring of the airways of the lungs, often due to repeated or severe infections. Bronchitis is inflammation of the large and small airways of the lungs.

Acute bronchitis is often due to a viral infection. Chronic bronchitis is a progressive lung disease due to smoking or environmental exposures. Pediatric bronchiolitis is inflammation of the smaller airways, typically caused by RSV, usually in children under 2 years of age. If your child is at high risk for RSV infection, your pediatrician may discuss palivizumab with you.

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Robledo-Aceves M, Moreno-Peregrina M, Velarde-Rivera F et al. Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department. Medicine (Baltimore). 2018;97(9):e0057. doi:10.1097/md.0000000000010057

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By Helen Massy
Helen Massy, BSc, is a freelance medical and health writer with over a decade of experience working in the UK National Health Service as a physiotherapist and clinical specialist for respiratory disease.