Which are the symptoms of Hypersensitivity Pneumonitis?

Symptoms of Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a lung disease caused by an immune response to inhaled environmental antigens. These antigens can include organic substances such as mold, bacteria, animal proteins, and chemicals. When a person with hypersensitivity to these substances breathes them in, their immune system reacts, leading to inflammation and damage to the lung tissue.

The symptoms of hypersensitivity pneumonitis can vary depending on the duration and intensity of exposure to the triggering antigens. They can also differ among individuals. The condition can be acute, subacute, or chronic, with each stage having its own set of symptoms.

Acute Hypersensitivity Pneumonitis

Acute hypersensitivity pneumonitis typically occurs within hours after exposure to the triggering antigen. The symptoms may include:

• Fever: A low-grade fever is common.


• Cough: A dry cough is often present.


• Shortness of breath: Difficulty breathing or breathlessness may occur.


• Chest tightness: A feeling of pressure or constriction in the chest.


• Fatigue: Generalized tiredness and lack of energy.


• Chills: Shivering or feeling cold despite normal temperature.


• Muscle aches: Joint and muscle pain can be experienced.

Subacute Hypersensitivity Pneumonitis

Subacute hypersensitivity pneumonitis develops over a period of weeks to months with repeated exposure to the antigen. The symptoms may include:

• Progressive shortness of breath: Breathlessness worsens over time.


• Chronic cough: A persistent cough that may produce phlegm.


• Weight loss: Unintentional weight loss may occur.


• Fatigue: Ongoing tiredness and lack of energy.


• Muscle and joint pain: Discomfort in the muscles and joints.


• Night sweats: Excessive sweating during sleep.


• Clubbing of fingers: The fingertips may become enlarged and rounded.

Chronic Hypersensitivity Pneumonitis

Chronic hypersensitivity pneumonitis develops over a long period of time, often years, with continuous exposure to the antigen. The symptoms may include:

• Gradual onset of shortness of breath: Breathlessness worsens slowly.


• Chronic cough: A persistent cough that may produce phlegm.


• Weight loss: Unintentional weight loss may occur.


• Fatigue: Ongoing tiredness and lack of energy.


• Clubbing of fingers: The fingertips may become enlarged and rounded.


• Cyanosis: Bluish discoloration of the lips, skin, or nails due to low oxygen levels.


• Respiratory failure: In severe cases, the lungs may fail to function properly.

If you experience any of these symptoms, it is important to seek medical attention for a proper diagnosis and treatment. Hypersensitivity pneumonitis can lead to irreversible lung damage if left untreated. Your healthcare provider may perform various tests, such as pulmonary function tests, chest X-rays, and blood tests, to confirm the diagnosis and determine the appropriate course of action.