Acute Bronchitis

Acute bronchitis is short-term swelling and irritation of the large airways in your lungs, usually caused by the same viruses that cause colds and flu. The main sign is a cough that can hang on for two to three weeks, often bringing up phlegm, and it usually settles on its own. It can leave you feeling wrung out and sore in the chest from coughing long after the fever and sore throat have gone.

What acute bronchitis is, and what it is not

Acute bronchitis is not the same as chronic bronchitis, although the names are close enough to cause real confusion. Chronic bronchitis means a cough with phlegm on most days for at least three months in two consecutive years, and it is part of COPD. Acute bronchitis is a single short illness that follows a viral infection and clears within a few weeks. If episodes keep coming back, a clinician may arrange spirometry, a breathing test, to check whether COPD is behind them.

It is also not usually a bacterial infection, and the colour of phlegm does not settle that question. Yellow or green phlegm is common in viral illness and does not on its own point to bacteria. Choosing Wisely Canada and the College of Family Physicians of Canada advise clinicians against antibiotics for respiratory infections that are likely viral or self-limiting. The main purpose of an assessment is not to decide about antibiotics but to rule out pneumonia and other causes.

Signs and symptoms

• A cough that lasts one to three weeks, sometimes bringing up clear, yellow or green phlegm
• Chest soreness, or a raw feeling from coughing
• Wheezing, or a whistling sound when breathing
• Feeling short of breath with activity
• A mild fever, chills or headache in the first few days
• A runny or blocked nose and sore throat before the cough starts
• Feeling tired and run down for a week or two

The pattern varies. Some people are over it in a week, while others cough for a month, and a cough that lingers after everything else has settled is common rather than unusual.

What raises the risk

Some things cannot be changed:

• Being aged 65 or older, when chest infections tend to hit harder
• Living with asthma, COPD or another long-term lung condition
• Having a weakened immune system from illness or medical treatment

Others can often be worked on, usually with support from a health care team:

• Smoking tobacco or vaping, which irritates the airway lining
• Second-hand smoke at home or at work
• Air pollution, wildfire smoke, workplace dusts, fumes and chemical vapours
• Close contact with people who have colds or flu, especially in crowded indoor settings

How acute bronchitis is diagnosed in Canada

Acute bronchitis is usually identified by a family doctor, nurse practitioner or pharmacist from your symptoms and a physical examination, including listening to your chest. No test confirms it. A chest X-ray may be ordered if there is fever, a fast heart rate or breathing rate, a low oxygen level, or sounds in the chest that do not fit, since the point of the assessment is to rule out pneumonia and other causes. During respiratory virus season a swab from the nose or throat may be tested for influenza, COVID-19 or RSV.

Treatment and day-to-day management

Clinical research for Acute Bronchitis is enrolling. See the current studies ↓

Most care for acute bronchitis is about comfort while the illness runs its course, and about making sure nothing more serious is being missed. Depending on your examination, your age and any long-term conditions you live with, a health care team may discuss:

• Supportive care, including rest, fluids and over-the-counter medicines for fever, aches or cough
• Assessment to rule out pneumonia, including chest imaging when the examination suggests it
• Inhaled bronchodilators, used in some people who have wheeze or an underlying airway condition
• Antiviral medicines in specific situations, such as confirmed influenza in people at higher risk of complications
• A review of whether an antibiotic has any role, which in Canadian primary care and emergency departments is guided by antimicrobial stewardship, since acute bronchitis is usually viral

Whether any of this applies to your illness depends on your own examination and history. These are decisions for you and your own clinician, and this page is not a recommendation about any of them.

When to talk to a doctor

• Call 911 if you have severe difficulty breathing, chest pain, confusion, blue or grey lips or fingertips, or you cough up a significant amount of blood.
• Seek medical care within a day if you have a high fever, shaking chills, breathlessness at rest, or symptoms that were improving and then suddenly got worse.
• Book an appointment if your cough lasts longer than three weeks, keeps returning, or you are aged 65 or older, pregnant, or living with a heart or lung condition or a weakened immune system.

Why clinical research matters for acute bronchitis

It is still unclear how a clinician can tell early on which people with an acute cough will get better on their own and which are developing pneumonia or a flare-up of an underlying lung condition. Antibiotic prescribing for acute bronchitis also varies widely between Canadian clinicians, and there is no agreed treatment that shortens the cough itself. Research now includes rapid point-of-care tests such as C-reactive protein and multiplex respiratory virus panels to guide antibiotic decisions, stewardship work in primary care, and studies of cough that persists after an infection has cleared.

Canada also has no national count of how often acute bronchitis occurs, which is part of why studies matter here. Taking part in one is voluntary, the study is explained to you in full during informed consent, and you can stop at any time without affecting the care you get from your own doctor. No one can say in advance whether a study will help you personally.

Learn more from Canadian sources

• Canadian Lung Association: Lung Health Information Line
• Choosing Wisely Canada: Using Antibiotics Wisely
• Public Health Agency of Canada: antibiotic prescribing for respiratory tract infection
• Government of Canada: respiratory syncytial virus (RSV)