Several risk factors have been identified which predispose a person to develop asthma. These differ for different age groups. For adult-onset asthma, the commonest risk factor that has been identified is a personal history of atopy, which has been described as a genetically determined predisposition to develop sensitivity to certain allergens (National Institutes of Health, 2003). This sensitivity manifests as an augmented IgE response to common aeroallergens, which can manifest clinically in one of the following ways, viz. asthma, allergic rhinitis or atopic dermatitis (Yates & deShazo, 2005). Having a personal or family history of atopy greatly increases the chance of developing asthma. It has been suggested that the presence of two out of the following three factors in an individual would greatly increase the probability of developing asthma, viz. presence of eosinophilia, a diagnosis of allergic rhinitis and occurrence of episodes of wheezing apart from episodes of colds (National Institutes of Health, 2003).
Apart from atopy, other risk factors which have been identified to play a role in the development of asthma include female gender, cigarette smoking and family history of asthma (Skrepnek & Skrepnek, 2004). In addition, aspirin sensitivity and exposure to occupational allergens including metals, wood dust and resins, are amongst other risk factors for asthma (Yates & deShazo, 2005)