We are offering Asthma is a condition caused by inflammation of the airways the small tubes that carry air in and out of the lungs. When a person with asthma comes into contact with something that irritates their airways (cats, dogs, pollen or even sporting activities), airways become narrower and the lining of the airways becomes inflamed and starts to swell. This makes it difficult to breathe and causes wheezing and coughing. Sometimes also, sticky mucus or phlegm builds up, which can further narrow the airways.