Facts

• Extrinsic asthma accounts for 90 percent of all childhood asthma cases.
  
  

Function

• When people with allergies encounter pollen, their immune systems overreact and produce excessive antibodies. In cases of extrinsic asthma, this reaction takes place in the lungs and leads to increased mucus production and difficulty breathing.
  
  

Effects

• Symptoms of extrinsic asthma include coughing, wheezing and chest pain.
  
  

Causes

• Heredity is a factor in extrinsic asthma. Families with a history of allergies are at greater risk for developing the condition.
  
  

Treatment

• Extrinsic asthma has no definite cure. Avoiding allergens is critical in controlling the condition. Extrinsic asthma is also treated with bronchodilators and antihistamines, as well as immunotherapy and prednisone, which is an inhaled steroid that suppresses the immune system.