. Cat allergy. A seven year old girl suffers an allergic reaction to her pet cat. The girl is using a tissue to blow her nose and wipe away tears. Such a reaction is caused by the effect of hairs and dust from the cat to the girl's immune system. The girl's immune system is mis-recognising this hair & dust as an invading organism. Mucus and tears are then produced to expel any tiny particles of cat hair or dust. This is known as a hypersensitivity reaction. Treatment is generally to avoid the object causing the reaction, however, drugs such as antihistamines can be used in more severe cases. MODEL RELEASED