Hypersensitivity Pneumonitis: Causes, Symptoms, Treatment, Prevention

Hypersensitivity pneumonitis also termed as allergic alveolitis is caused due to alveolar inflammation in the lungs due to extreme sensitivity as a result of inhaling organic dust, which the people are generally exposed to in the course of their occupation or pursuing their hobbies. Hypersensitivity pneumonitis is caused due to inhalation of an antigen resulting in an excessive immune response. During the initial stages, an individual may not experience any problem, but as time passes by with chronic exposure to these particulates the individual may start to experience respiratory symptoms as the alveoli start getting inflamed and there may be buildup of fluid in these air sacs as well. As the exposure increases, the disease condition can start flaring up causing formation of scar tissues in the lungs affecting the normal functioning of the lungs.

Hypersensitivity Pneumonitis as stated is caused by inhalation of particulates to which the body is allergic to. This condition is caused over a prolonged period of exposure to the allergen, which may span several years. Normally, people who work in areas where there is abundant amount of dust that may contain fungus, molds etc.

Hypersensitivity Pneumonitis can also develop from humidifiers and air conditioners, especially if they are not appropriately serviced and maintained. Certain bird droppings can also cause Hypersensitivity Pneumonitis. Some of the other causes of Hypersensitivity Pneumonitis can be from inhalation of dust from:

• Moldy sugarcane
• Barley
• Animal hair
• Bird droppings
• Coffee beans

At present, there is no definitive cure for Hypersensitivity Pneumonitis, but fortunately this condition is definitively reversed if the exposure to the offending allergen is stopped. Prolonged inhalation of the allergen can cause scarring of the lungs or pulmonary fibrosis. Once this occurs, then the damage to the lungs becomes permanent and treatment is focused on controlling symptoms.

The symptoms of hypersensitivity pneumonitis are divided into three types namely, acute, subacute, and chronic.

• Acute: In the acute form of infection, the symptoms can start to develop within 6 hours to the exposure to the offending antigen and may include fever, chills, cough, chest pressure, shortness of breath, headache. These symptoms take several days to resolve until the exposure clears off. In acute hypersensitivity pneumonitis, the chest radiographs shows ground glass opacities and radiodensity.
• Subacute: In subacute form of hypersensitivity pneumonitis, people experience a productive cough, shortness of breath, lethargy, loss of weight. In the subacute form, the symptoms are less severe than the acute form but they tend to last longer.
• Chronic: In the chronic form, patients have a spontaneous onset of cough, progressive shortness of breath, lethargy, and have loss of weight. In such cases, avoidance of further exposure to the offending antigen is recommended. Inspiratory crackles are also noted in some patients.

To diagnose Hypersensitivity Pneumonitis, the treating physician will take a detailed history in order to look for any exposure to dust that may be linked to the symptoms. A detailed physician examination will also be conducted to observe the functioning of lungs. The physician may look for any adventitious sounds in the lungs.

• Blood draws
• Scrutinizing workplace to look for presence of molds and other allergens
• Chest x-ray
• CT scan of chest
• Pulmonary function tests
• Lung biopsy

The cornerstone of treatment for Hypersensitivity Pneumonitis is to identify it in the earlier stages as this disease is completely reversible if diagnosed and treated early. Once into the chronic stages, symptoms need to be controlled and for this basically steroids are used as other forms of medications are not effective. Smoking cessation is imperative in Hypersensitivity Pneumonitis in case if an affected individual is a smoker, as cigarette smoke worsens the condition and may cause potentially serious complications like emphysema or chronic bronchitis.

Appropriate drying and storing farm products goes a long way in preventing Hypersensitivity Pneumonitis as the offending fungus grows in moist conditions. Adequate ventilation is also imperative in preventing Hypersensitivity Pneumonitis. As stated, Hypersensitivity Pneumonitis is completely curable and reversible if diagnosed and treated in the initial stages.