Asthma is a common condition affecting the tubes in the lungs called bronchioles, the condition can make it difficult to breathe. An asthma attack can be brought on by many factors including things that are inhaled, such as dust, pollen, cigarette smoke and animal fur. An attack can also be induced by swallowing things such as certain medicines. Other factors such as exercise, cold air, stress or a chest infection could also trigger an attack.