Allergies can develop at any age. Though allergies occur most commonly in children, some people may experience symptoms for the first time in their adulthood. Nasal allergies tend to decline with age, but asthma may persist in adults.
Your risk of developing allergies is related to your parents allergy history. Though you may still develop allergies even if none of your parents have allergies, your chances of getting them are very slim compared to individuals who have at least one parent with a history of allergies. The chances are even higher if both parents of an individual have allergies.
Even if a person inherited the tendency to develop allergies, the person may never actually have allergy symptoms. The type of allergies or diseases a person may inherit from his or her parents also might not necessarily be the same. The determining factors to which substances will trigger a reaction in an allergic person, which diseases might develop or how severe the symptoms might be is still unknown.
In addition to having a genetic tendency, you must also be in an environment where you are exposed to an allergen in order to develop an allergy. The person will also be more likely to develop an allergy with increased intensity and repetitive exposure to an allergen and if the exposure occurs early on in life.
Other important influences that may contribute to cause allergic conditions include smoking, pollution, infection, and hormones.