Allergies can affect anyone, regardless of age, gender, race, or socioeconomic status. Generally, allergies are more common in children. However, a first-time occurrence can happen at any age, or recur after many years of remission.
There's a tendency for allergies to occur in families, although the exact genetic factors that cause it aren't yet understood. In susceptible people, factors, such as hormones, stress, smoke, perfume, or other environmental irritants, may also play a role. Often, the symptoms of allergies develop gradually over a period of time.
Allergy sufferers may become so accustomed to chronic symptoms, such as sneezing, nasal congestion, or wheezing, that they don't consider their symptoms to be unusual. Yet, with the help of an allergist, these symptoms can usually be prevented or controlled and quality of life greatly improved.