Once an allergic reaction has occurred, very small quantities of a substance may produce respiratory illness, such as :

• Asthma
  Wheezing, chest tightness and breathlessness.

• Extrinsic Allergic Reaction
  Breathlessness and flu-like symptoms.

• Rhinitis
  Runny nose and nasal congestion.

Once a person is sensitized, continued exposure can result in permanent damage to his lings and increasingly severe symptoms. People with Rhinitis may go on to develop Asthma. Asthma attacks are likely to become worse and can be triggered by other things such as tobacco smoke, general air pollution or even cold air.