Bronchitis vs. Pneumonia: What Are the Differences Between Them?

You're coughing, wheezing, short of breath. Your chest feels tight. Something has infected your respiratory tract or lungs. But what is it -- bronchitis or pneumonia?

They are not the same illness. Although they share similar causes and symptoms, there are important differences between bronchitis and pneumonia. The main difference is where the infection is located.

"Bronchitis is an infection of the lung air passages, and pneumonia is an infection of the lung air sacs," says Dr. MeiLan K. Han, professor of internal medicine in the division of pulmonary and critical care medicine at the University of Michigan Health System and director of the Michigan Airways Program.

That's not the only difference, however. Yet they are sometimes so similar, even your doctor will be hard-pressed to make a correct diagnosis. "It can be difficult to distinguish between the two without a chest X-ray," Han says.

Proper diagnosis is critical because knowing what you have determines how you should be treated.

[Read: How to Tell if It's Burnout or the Common Cold.]

What Is Bronchitis?

Acute bronchitis, according to the American Lung Association, is a lower respiratory tract inflammation affecting one or both of the air tubes, called bronchi, that connect the esophagus to the lungs. Like other respiratory infections, it usually comes on suddenly and can last for three to 10 days, with the average being about a week.

The bronchial tubes can become irritated, infected or inflamed by several things, including:

-- Tobacco or other types of smoke.

-- Chemical fumes.

-- Dust.

-- Air pollution.

-- A respiratory virus or, occasionally, a bacterial infection.

These irritants infect the cells that line the bronchi. Sometimes the infection begins in the nose or throat, then spreads to the bronchial tubes. As the immune system tries to fight off the infection, the bronchial tubes swell, causing you to cough. The cough may be dry, but usually it produces mucus. The swelling also makes it harder to breath, as airflow is restricted. This can result in wheezing, a tight feeling in the chest and shortness of breath.

As with most other respiratory infections like a cold or the flu, bronchitis usually is resolved by the body's immune system. It just takes a few days to a week. However, the ALA says that you may continue to cough and produce mucus for several weeks after the infection has cleared.

[See: 14 Myths and Misconceptions About the Flu Vaccine.]

Acute bronchitis is usually a short-term disease with no lasting or permanent breathing difficulties. But people with weakened immune systems or other health problems may develop more severe breathing issues, such as pneumonia or respiratory failure. Those most at risk for these major problems are:

-- The elderly.

-- Young children.

-- People with cancer, diabetes or other major health issues.

-- People who have not been immunized for the flu, pneumonia and whooping cough.

Your doctor will diagnose bronchitis by taking a history of your symptoms and doing a physical examination. He or she may order a chest X-ray to make sure it's not pneumonia, but most often the doctor can tell the difference without it. As with colds, there aren't any treatments for the disease itself. Most cases are caused by environmental irritants or viruses, which do not respond to antibiotics. Only time and your immune system will take care of that. You can treat the symptoms with rest, drinking plenty of fluids and a cough suppressant and pain reliever.

To prevent bronchitis, the ALA recommends:

-- Don't smoke.

-- Avoid lung irritants. Protect your lungs by wearing a mask over your mouth and nose when using lung irritants such as paint, paint remover or varnish.

-- Wash your hands often to reduce your exposure to viruses and bacteria.

-- Get a flu shot every year.

-- Ask your doctor if you should get a pneumonia shot, especially if you're 60 or older.

What Is Pneumonia?

Bronchitis is far more common than pneumonia, says Dr. Cedric "Jamie" Rutland, a pulmonary and critical care physician and assistant clinical professor at the University of California--Riverside. "Nine out of 10 people who think they have pneumonia actually have bronchitis. But they are two completely different illnesses."

Pneumonia is different from bronchitis in many important ways. First, the infection occurs deep in the lungs themselves, not in the bronchial tubes. The infection can be caused by bacteria, viruses (including the influenza virus) or fungi that affect air sacs in the the lungs, called alveoli, to become inflamed and fill up with fluid or pus. This makes it hard for the lungs to take oxygen out of the air you breathe and get it into the bloodstream.

Some of the symptoms of pneumonia are similar to bronchitis: cough, wheezing, shortness of breath. But in more serious cases they can also include a high fever and chills, sweating, rapid breathing and elevated heart rate. Breathing may cause sharp, stabbing pain. Lack of oxygen can cause the lips and fingernails to turn blue. Pneumonia is a leading cause of hospitalization in both children and adults, the ALA says. The severity of the disease depends on the type of virus or bacteria, age and overall health.

[See: 9 Ways to Boost Your Immune System.]

Those most at risk for serious complications from pneumonia include:

-- Infants and young children.

-- Adults age 65 and older.

-- Those with other health problems or compromised immune systems.

Pneumonia kills tens of thousands of people in the U.S. every year, most of them adults over 65, the ALA says. But most cases can be treated successfully, though it can take several weeks to recover fully.

Pneumonia can be hard to diagnose because the symptoms often look like a cold, the flu or bronchitis. The doctor will take a history of your symptoms and listen to your lungs with a stethoscope. With pneumonia, the lungs make crackling, bubbling and rumbling sounds on inhalation, the ALA says. If pneumonia is suspected, a blood test and chest X-ray can confirm the cause and location of the infection.

" Walking pneumonia," a nonmedical term for a mild case of pneumonia, is medically known as atypical pneumonia. It can be caused by a virus but is most often caused by a common bacterium called Mycoplasma pneumonia, the ALA says. The symptoms are usually so mild that bed rest or a trip to the hospital aren't necessary, and people carry on with daily activities -- thus the term "walking."

Treatment depends on the type and severity of the pneumonia, age and other health conditions. Bacterial pneumonia typically will be treated with an antibiotic, Rutland says. Viral pneumonia is less common, and antibiotics won't help.

"Your immune system will generate antibodies to combat the virus," he says, though it usually takes seven to 10 days before symptoms diminish. For those who are taking immunosuppressant medications or are otherwise immune-compromised, viral pneumonia "becomes very, very difficult to treat," Rutland says, and requires antiviral drugs, which are not as effective as antibiotics are in treating bacteria.

For most cases, though, symptom control -- pain relievers, fluids and plenty of rest -- are the best your doctor can offer.