Pathogenesis
There is a decrease in the lumen of the air ways resulting from a two fold response to the allergens and other irritants.
Primarily in a hyper reactive response, the smooth muscles in the airways constrict and narrow excessively. Followed by an inflammatory response where the immune system responds to the allergens by sending white blood cells and other immune factors to the airways. These inflammatory factors cause a swelling of the airways and also an increase in the mucus secretion thus causing symptoms like wheezing, cough and shortness of breath.
Prevalence
Children aged 2-12 years reported higher rates of asthma (15.7%) than adults aged 16 years and over (10.1%). In males, the prevalence of asthma was highest among children aged 2-12 years; in females, prevalence was highest among young adults aged 16-24 years. Asthma is also closely linked to allergies. Most, but not all, people with asthma have allergies. Children with a family history of allergy and asthma are more likely to have asthma.
