Hypersensitivity Pneumonitis (HP), Idiopathic Pulmonary Fibrosis (IPF), Interstitial Lung Disease (ILD) and Other Respiratory Diseases


Understanding Hypersensitivity Pneumonitis: Causes and Symptoms

Hypersensitivity Pneumonitis (HP) (aka farmer’s lung)

Hypersensitivity pneumonitis (HP) is a disease that occurs when a person breathes in substances that cause their lungs to become inflamed. Examples of substances that cause inflammation (called antigens) are mold, dusts, and chemicals. Although many people come into contact with these antigens at work or home, only some will develop hypersensitivity pneumonitis. In 2004, the Institutes of Medicine found sufficient evidence of a link between exposure to indoor mold and HP in susceptible patients.

Hypersensitivity pneumonitis can be acute (short-term) or chronic (long-term). Symptoms of acute HP include chills, body aches, coughing, and chest tightness. After hours or days of no contact with the antigen, symptoms usually go away. However, if the antigen remains present, acute HP can develop into chronic HP. Chronic HP can cause a worsening cough, shortness of breath with physical activity, fatigue, and weight loss. Severe HP may cause clubbing, which is a widening and rounding of the tips of the fingers or toes. Researchers are still investigating why exposure to antigens causes HP in some people but not others.

Although some medications (such as corticosteroids or prednisone) can control symptoms, HP is a clear case of an ounce of prevention being worth a pound of cure. Preventing HP means avoiding exposure to the antigen that caused the initial acute case; if you are able to reduce or prevent contact with the antigen that caused your disease, you will succeed in preventing HP from developing. If you have been diagnosed with either acute or chronic HP, you must find out which antigen caused your illness and take steps to reduce or eliminate contact with that substance.

Ground glass opacity visible in lung X-rays of a person with Hypersensitivity Pneumonitis (HP) and Idiopathic Pulmonary Fibrosis (IPF)

Pulmonary Fibrosis (PF)

Pulmonary fibrosis (PF), also called idiopathic pulmonary fibrosis (IPF) is part of the group known as interstitial lung diseases which cause scarring in the lungs. Tissue deep inside the lungs becomes scarred and stiffened (this is called fibrosis) and makes it difficult to breathe. PF is a serious disease and is most likely to affect people aged 50-75. There are dozens of possible causes for PF, and in many cases, doctors cannot pinpoint the exact cause of an individual’s disease. Exposure to environmental hazards such as asbestos, silica, mold, and bird or animal droppings may cause PF; other possible causes include some medications, radiation, and other health conditions. The lung scarring caused by PF cannot be cured, but some medications can slow the progression of the disease, along with lifestyle changes to preserve your health to the extent possible.

Interstitial Lung Disease (ILD)

Interstitial lung disease describes a large group of lung disorders characterized by progressive scarring in the lungs. Scarring in the lungs causes problems because, over time, it stiffens lung tissue, making it more difficult to breathe. For some patients, the cause is unknown (this is known as idiopathic interstitial lung disease); however, for most patients, interstitial lung disease is caused by an environmental exposure or by medication. Environmental exposures that can cause interstitial lung disease include asbestos, mold, silica, coal dust, grain dust, and bird protein (from feathers). Other causes may be radiation, chemotherapy drugs, some heart medications, some antibiotics, and some autoimmune conditions. If you are concerned about interstitial lung disease and medication, your doctor can tell you if you are at risk.

Lung scarring from interstitial lung disease is usually irreversible, but some medications can control inflammation and slow or prevent new scarring. However, prevention is always the best way to protect your health. Interstitial lung disease can be prevented by reducing or preventing environmental exposures at home and at work. An environmental health investigator can tell you if you are at risk from asbestos, mold, silica, or any other environmental factors in your home.


Chronic Obstructive Pulmonary Disease (COPD) is a progressive condition in which the bronchioles (small air passages) of the lungs become clogged or lose their shape. It is the third most common cause of death in the United States, affecting an estimated 24 million Americans (source). Although COPD may begin with few symptoms, as the disease progresses, they often become worse. Symptoms include an ongoing cough that may produce mucus (often called “smoker’s cough”), shortness of breath, especially with physical activity, wheezing, and chest tightness. COPD is caused by exposure to environmental irritants; by far the most common cause is cigarette smoke, but long-term exposures to other irritants such as dusts, chemicals or air pollution can also contribute to COPD.

Although COPD currently has no cure, there are many treatments that can make the disease more manageable. There are oral and inhaled medications which can alleviate symptoms, and there are lifestyle changes, such a quitting smoking, which can slow the progression of the disease. It is also wise to take care not to expose yourself to environmental irritants which can worsen symptoms, such as aerosols, dusts, and mold. Mold spores circulating in the air can cause opportunistic fungal infections if inhaled by COPD patients. If you or someone in your family has been diagnosed with COPD, an indoor air quality investigation can help determine the best ways to protect your health and the health of your family.


Silicosis is a lung disease caused by breathing in tiny particles of silica, a mineral that is part of sand, rock, and mineral ores such as quartz. Over time, silicosis causes scarring in the lungs and affects sufferers’ ability to breathe. Silicosis is most often an occupational disease; people most likely to be diagnosed with it are people working in industries such as construction, mining, and glass manufacturing. About 2 million American workers are currently at risk for silicosis. (source) There are three types of silicosis: acute, chronic, and accelerated. Although each has unique symptoms, all three types make it difficult to breathe. Silicosis can be a very serious condition, causing over 100 deaths per year in the United States (source). Although silicosis cannot be cured, it can be managed, and, most importantly, it can be prevented.

The best way to prevent silicosis is to keep dust out of the air. During any construction or demolition work, dust control measures are essential. This can be as simple as using water to wet dust and keep it from blowing into the air, using dust masks, and using proper tools with dust control or dust collection features. If you are planning to do any type of renovation work yourself, be sure to use the correct personal safety equipment, and keep your work area as clean as possible. If construction in or around your building has you concerned about silica, an indoor air quality inspection can give you a clearer picture of any potential exposures and help you plan the best way to protect your health.


Asbestosis is a lung disease caused by exposure to asbestos fibers in the air. Asbestos is a naturally-occurring mineral which in the past was used as building insulation. Thanks to changes in health regulations over the past 50 years, asbestos is becoming rarer and rarer, and most people with asbestosis today were exposed before the 1980s. However, some older homes may still have insulation, vinyl flooring, or other materials that contain asbestos. If you are concerned about the possibility of asbestos in your home, an environmental health specialist can perform an inspection to determine whether you are at risk. Although exposed asbestos is a health hazard, asbestos which is sealed away from the air is far less likely to cause illness, and in some cases it is safer to leave it undisturbed.

Asbestosis can take up to 20 years after exposure to show symptoms. Symptoms include: shortness of breath, persistent dry cough, chest tightness, chest pain, loss of appetite and weight loss, a dry, crackling sound in the lungs while breathing in, and wider and rounder than normal fingertips and toes (clubbing). Asbestosis cannot be cured, but it can be managed by maintaining your health through proper nutrition, exercise, avoiding infections, and avoiding bad air by staying inside when pollution or pollen counts are high and avoiding irritants and pollutants.


Aspergillosis is a disease caused by Aspergillus, a common type of mold that lives indoors and out. Most people breathe in Aspergillus spores every day without getting sick. However, some vulnerable groups, like people with lung diseases or compromised immune systems, may contract aspergillosis from mold exposure. There are many types of aspergillosis, ranging from mild to severe. According to the Centers for Disease Controls, the most common types are:

  • “Allergic bronchopulmonary aspergillosis (ABPA): Aspergillus causes inflammation in the lungs and allergy symptoms such as coughing and wheezing, but doesn’t cause an infection.
  • Allergic Aspergillus sinusitis: Aspergillus causes inflammation in the sinuses and symptoms of a sinus infection (drainage, stuffiness, headache) but doesn’t cause an infection.
  • Aspergilloma: also called a “fungus ball.” As the name suggests, it is a ball of Aspergillus that grows in the lungs or sinuses, but usually does not spread to other parts of the body.
  • Chronic pulmonary aspergillosis: a long-term (3 months or more) condition in which Aspergillus can cause cavities in the lungs. One or more fungal balls (aspergillomas) may also be present in the lungs.
  • Invasive aspergillosis: a serious infection that usually affects people who have weakened immune systems, such as people who have had an organ transplant or a stem cell transplant. Invasive aspergillosis most commonly affects the lungs, but it can also spread to other parts of the body.
  • Cutaneous (skin) aspergillosis: Aspergillus enters the body through a break in the skin (for example, after surgery or a burn wound) and causes infection, usually in people who have weakened immune systems. Cutaneous aspergillosis can also occur if invasive aspergillosis spreads to the skin from somewhere else in the body, such as the lungs.” (source for the above list)

Symptoms of milder forms of aspergillosis include cough, fever, wheeze and shortness of breath. In more serious infections, symptoms may also include chest tightness and coughing up blood. Preventing aspergillosis can be difficult, since the spores occur naturally in most environments. However, if you are at risk of contracting aspergillosis, it is important that you take steps to protect your health. Avoid dusty areas if possible, and if you cannot avoid them, wear an N95 respirator (a medical face mask available at most pharmacies). Monitor your home environment for dampness or mold growth, and use a HEPA air filter to keep the air clean. Your doctor may also prescribe antifungal medication or perform regular blood tests to detect aspergillosis early on. Aspergillosis can be serious, but with proper monitoring of your health and your environment, it can be prevented.

Legionellosis (aka Legionnaire’s disease, aka Pontiac fever)

Legionellosis is a disease caused by the Legionella bacterium; when it infects the lungs and causes pneumonia, it is called Legionnaire’s disease. The bacterium is found naturally in fresh water, but grows best in warm water, like the kind found in hot tubs, cooling towers (air-conditioning units for large buildings), hot water tanks, large plumbing systems, and decorative fountains. People are exposed to Legionella when they breathe in mist or vapor containing the bacteria; legionellosis cannot be passed from person to person. Most people who are exposed to Legionella do not become ill. However, if you are concerned that you have been exposed to the bacterium, contact your doctor or you local health department.

Legionella causes two diseases: Legionnaire’s disease and Pontiac fever. Legonnaire’s disease can be difficult to diagnose because its symptoms appear very similar to other types of pneumonia. Common symptoms include: cough, shortness of breath, high fever, muscle aches, and headache. Although most healthy people who contract Legionnaire’s disease will recover after treatment with antibiotics, the disease can be serious, and most patients will have to be hospitalized. Symptoms of Legionnaire’s disease usually begin between 2-10 days after exposure, so if you think you have been exposed to Legionella, monitor your health for two weeks. Pontiac fever has similar symptoms to Legionnaire’s disease, but it is a milder infection that does not cause pneumonia. Antibiotics will not help with Pontiac fever, which usually goes away on its own without specific treatment. To prevent legionellosis, ensure that water tanks, hot tubs, and other warm-water systems are properly maintained.


Bronchitis is an inflammation of the lining of the bronchial tubes, which carry air in and out of the lungs. The main symptom of bronchitis is a cough which produces mucus. Some people may also experience fatigue, shortness of breath, and slight fever. There are two types of bronchitis: acute and chronic. Acute bronchitis will usually go away on its own after a few days, although the cough can linger for weeks afterward. Because acute bronchitis is caused by a virus, antibiotics will not help with the disease. If you are concerned that you may have acute bronchitis, talk to your doctor about over-the-counter remedies that will ease your symptoms.

Chronic bronchitis is defined as a productive cough (a cough that produces mucus) that lasts for more than three months, with recurring bouts for at least two consecutive years. Chronic bronchitis sufferers may have periods when their symptoms worsen, and may develop acute bronchitis on top of their chronic bronchitis. The most common cause of chronic bronchitis is cigarette smoke, including secondhand smoke. Other risk factors include gastric reflux and exposure to environmental irritants. If you live or work in an environment where you are exposed to dust, textiles, or chemical fumes, an environmental health investigation can help determine your risk for developing bronchitis.

Mycobacterium Avium Complex (MAC)

Mycobacterium Avium Complex (MAC) is a bacterium found in all parts of the environment. MAC is found in dust, water and food, and almost everyone has the bacterium in their bodies. Most people will not get sick from MAC. However, those with compromised immune systems, especially people with HIV/AIDS, are at risk of infection from MAC. Symptoms of MAC infection include fever, chills, diarrhea, weight loss, stomach aches, fatigue and anemia. Because these symptoms are similar to those of many opportunistic infections (infections that are most dangerous to people with weakened immune systems), MAC disease can be difficult to diagnose, and can take root in different parts of the body. MAC disease can be treated with a variety of antibiotics. However, if you have HIV or AIDS, it is important to maintain your health by taking your medications correctly; this is the best way to prevent MAC infection.


Cryptococcosis is a disease caused by the fungus Cryptococcus neoformans. It is usually found in soil; because it is so ubiquitous, it is difficlut to avoid exposure. Cryptococcosis infection is extremely rare in healthy people. Those most at risk of infection are patients with compromised immune systems, such as people with HIV/AIDS, or Hodgkin’s disease, and patients who take high-dose corticosteriods or are undergoing chemotherapy. Although cryptococcosis can be treated with antifungal medications, it has the potential to to become a very serious infection.