The most important of these factors are allergens and chemical sensitizes. Contributing factors - risk factors that either augment the likelihood of asthma developing upon exposure to them, or may even increase susceptibility to asthma. These factors including smoking, viral infections, small size at birth, and environmental pollutants. Environmental control - removal of risk factors from the environment. Exacerbation - any worsening of asthma.
Onset can be acute and sudden, or gradual over several days.
A correlation between symptoms and peak flow is not necessarily found. PEF home monitoring is especially useful to patients over 5 years of age with moderate persistent to severe persistent asthma. Risk factor - an agent that when present increases the probability of disorder expression. Alternatively, a risk factor can be due to environmental exposure. Risk factors that cause asthma exacerbation in individuals who already have the condition.