Generally there are three risk factors which increase the chances an individual will develop asthma. The first is atopy; a genetic tendency to develop allergic responses to various triggers. Atopy is the most common risk factor and it is associated with allergic asthma, atopic dermatitis, allergic rhinitis, etc. Gender is a factor in that females are more likely to experience asthma after puberty, while males are more likely to experience asthma before puberty. Additionally environmental factors, including air pollution and smoke exposure can contribute to the problem.
Following the onset of asthma, various triggers can stimulate exacerbations. These include occupational triggers (such as chemicals, dusts and particulates, vapors, gases, and aerosols29), respiratory infections, gastroesophageal reflux disease (GERD), seasonal allergens, cold air, pollutants, hormonal changes, exercise, aspirin and NSAIDs. Asthma patients have various degrees of sensitivity and reactivity to triggers. Many triggers assault the respiratory mucosa directly, inducing asthma symptoms in response. Others, such as aspirin-induced asthma increase inflammatory mediators.23