When you think of chronic lung disease, you may think of lung cancer, but there are actually many different types. Altogether, lung diseases accounted for more than 1 million deaths in the U.S. in 2010, according to the National Heart, Lung, and Blood Institute (NHLBI).

These types of lung diseases may affect your airways, lung tissues, or circulation of blood in and out of your lungs. Here are the most common types, their causes and risk factors, and potential symptoms that may signal the need for medical attention.

Asthma is one of the most common types of chronic lung disease. When triggered, your lungs become swollen and narrow, making it harder to breathe. Symptoms include:

  • wheezing
  • being unable to take in enough air
  • coughing
  • feeling tightness in your chest

If you experience these symptoms, it’s important to see a doctor right away. Triggers may include allergens, dust, pollution, stress, and exercise.

Asthma usually starts in childhood, though it can begin later. It can’t be cured, but medications can help control symptoms. The disease affects about 26 million Americans and tends to run in families.

Most people with asthma can manage it fine and enjoy full and healthy lives. Without treatment, though, the disease can be deadly. It kills about 3,300 people annually in the United States.

Doctors don’t know yet why some people get asthma and others don’t. But they believe that genetics play a large role. If someone in your family has it, your risk goes up.

Other risk factors include:

  • having allergies
  • being overweight
  • smoking
  • being exposed frequently to pollutants

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease in which your lungs become inflamed, making breathing more difficult. The inflammation leads to an overproduction of mucus and a thickening of the lining of your lungs. The air sacs, or alveoli, become less efficient at bringing oxygen in and sending carbon dioxide out.

People with COPD typically have one or both of the following conditions:

Emphysema: This disease damages the air sacs in your lungs. When healthy, the air sacs are strong and flexible. Emphysema weakens them and eventually causes some to rupture.

Chronic bronchitis: You may have experienced bronchitis when you had a cold or sinus infection. Chronic bronchitis is more serious, as it never goes away. It causes inflammation of the bronchial tubes in your lungs. This increases mucus production.

Symptoms of emphysema include:

  • shortness of breath
  • wheezing
  • the feeling of not being able to get enough air

Symptoms of chronic bronchitis include:

  • frequent coughing
  • coughing up mucus
  • shortness of breath
  • chest tightness

COPD is an incurable, progressive disease most often caused by smoking, though it also has a powerful genetic component. Other risk factors include:

  • exposure to secondhand smoke
  • air pollution
  • occupational exposure to dust, fumes, and smoke

Symptoms of COPD get worse over time. However, treatments can help slow progression.

A number of different lung diseases fit under the umbrella term “interstitial lung disease.” Interstitial lung diseases include over 200 types of lung disorders. A few examples:

  • sarcoidosis
  • idiopathic pulmonary fibrosis (IPF)
  • Langerhans cell histiocytosis
  • bronchiolitis obliterans

The same thing happens with all of these diseases: The tissue in your lungs becomes scarred, inflamed, and stiff. Scar tissue develops in the interstitium, which is the space in your lungs between the air sacs.

As the scarring spreads, it makes your lungs more rigid, so they’re unable to expand and contract as easily as they once did. Symptoms include:

  • a dry cough
  • shortness of breath
  • difficulty breathing

You may be more at risk if someone in your family had one of these diseases, if you smoke, and if you’re exposed to asbestos or other inflammatory pollutants. Some autoimmune diseases have also been linked to interstitial lung disease, including rheumatoid arthritis, lupus, and Sjogren’s syndrome.

Other risk factors include going through radiation for cancer treatments, and taking some medications like antibiotics and prescription heart pills.

These diseases are incurable, but newer treatments hold promise for slowing their progression.

Pulmonary hypertension is simply high blood pressure in your lungs. Unlike regular high blood pressure, which affects all the blood vessels in your body, pulmonary hypertension affects only those blood vessels between your heart and lungs.

These blood vessels become narrowed and sometimes blocked, as well as stiff and thick. Your heart has to work harder and push the blood more forcefully, which increases the blood pressure in lung arteries and capillaries.

Gene mutations, drugs, and congenital heart diseases can all cause pulmonary hypertension. Other lung diseases like interstitial lung disease and COPD may also be to blame. If left untreated, the condition can lead to complications like blood clots, arrhythmia, and heart failure.

Risk factors for pulmonary hypertension include:

  • being overweight
  • having a family history of the disease
  • having another lung disease
  • using illegal drugs
  • taking certain medications, like appetite-suppressant drugs

Symptoms include:

  • shortness of breath
  • chest pain
  • dizziness
  • fatigue
  • rapid heart rate
  • edema (swelling) in your ankles

This disease can’t be cured, but treatments can help lower the pressure to a more normal level. Options include medications like blood thinners, diuretics, and blood vessel dilators. Surgery and transplantation are reserved as last resorts.

Cystic fibrosis is an inherited lung disease that affects newborn children. It changes the makeup of mucus in the body. Instead of being slippery and watery, mucus in a person with cystic fibrosis is thick, sticky, and excessive.

This thick mucus can build up in your lungs and make it more difficult to breathe. With so much of it around, bacteria grow more easily, increasing risk of lung infections.

Symptoms usually start in infancy and include:

  • chronic coughing
  • wheezing
  • shortness of breath
  • coughing up mucus
  • recurring chest colds
  • extra salty sweat
  • frequent sinus infections

According to the NHLBI, it can affect other organs in addition to the lungs, including your liver, intestines, sinuses, pancreas, and sex organs.

Doctors know that cystic fibrosis is caused by a gene mutation that normally regulates the level of salt in cells. The mutation causes this gene to malfunction, changing the makeup of mucus and increasing salt in sweat. There is no cure for the disease, but treatment eases symptoms and slows progression.

Early treatment is best, which is why doctors now regularly screen for the disease. Medications and physical therapy help loosen mucus and prevent lung infections.

Pneumonia is a lung infection caused by bacteria, viruses, or fungi. Microorganisms grow and thrive in the lungs, creating difficult symptoms. The air sacs become inflamed and may fill up with fluid, which disrupts the flow of oxygen. Most of the time people recover within a few weeks. Sometimes, though, the disease hangs on, and may even become life-threatening.

Pneumonia can attack anyone, but it’s most likely to develop in people whose lungs are already vulnerable because of:

  • smoking
  • a weakened immune system
  • another illness
  • surgery

Many times, pneumonia can be cured. Antibiotics and antiviral medications can help, and with time, rest, and fluids, the disease will often go away. In some cases, though, it can come back again and again, becoming a chronic disease.

Symptoms of chronic pneumonia include:

  • coughing up blood
  • swollen lymph nodes
  • chills
  • lasting fever

The symptoms may continue for a month or longer. Even if you take antibiotics, the symptoms may return when you finish them.

If regular treatments don’t work, your doctor may recommend hospitalization so you can have access to additional treatment and rest. Possible complications of chronic pneumonia include lung abscesses (pus pockets in or around your lungs), uncontrolled inflammation in your body, and respiratory failure.

Lung cancer is a disease in which the cells in your lungs grow abnormally, gradually developing tumors. As the tumors get bigger and more numerous, they can make it more difficult for your lungs to do their job. Eventually, the cancerous cells can spread to other areas of your body.

Lung cancer is the leading cause of cancer death in the U.S., according to the Mayo Clinic. It can grow for awhile without creating any symptoms. When symptoms do develop, they are often thought to be caused by other conditions. A nagging cough, for example, can be a symptom of lung cancer, but it can be caused by other lung diseases as well.

Other possible symptoms of lung cancer include:

  • wheezing
  • shortness of breath
  • unexplained weight loss
  • coughing up blood

Those most at risk include those who:

  • smoke
  • are exposed to dangerous chemicals by inhalation
  • have a family history of lung cancer
  • have other types of cancer

Treatment depends on the type of lung cancer and its severity. Your doctor will typically create a plan that includes surgery to remove the cancerous part of the lung, chemotherapy, and radiation. Some medications can also help target and kill cancerous cells.

To increase your odds of avoiding chronic lung disease, consider these tips:

  • Don’t smoke, or quit smoking. Avoid secondhand smoke.
  • Try to reduce your exposure to pollutants in the environment, at work, and in your home.
  • Exercise regularly. Aerobic exercise that increases your heart rate is best.
  • Eat a nutritious diet.
  • Get regular checkups with your doctor.
  • Be sure to get a flu shot every year, and after you turn 65, get a pneumonia shot.
  • If you’re at risk for lung cancer, ask your doctor about screening options.
  • Test your home for radon gas.
  • Wash your hands regularly, avoid touching your face, and stay away from individuals who are sick.