Allergies are ubiquitous. Many teenagers are sensitive to atopic diseases, whereas a sizeable chunk of the world population will test positive during a skin-prick test. Although differentiating the allergies from viral upper respiratory system diseases is difficult, younger population is more prone to allergies. And, both environmental and genetic factors play an important role in allergic disorders. 

Atopy, a genetic factor, implies production of immunoglobulin E (IgE) in the presence of environmental protein allergens. The continuous production of IgE causes atopic diseases, including allergic rhinitis, asthma and eczema. Allergic rhinitis is generally divided into three categories: occupational, perennial and seasonal. Occupational allergic rhinitis develops due to allergens found in the work environment, like certain chemicals.  Perennial allergic rhinitis is mainly ascribed to animal dander, cockroaches, molds, dust mites and other indoor allergens. Seasonal allergic rhinitis is associated with an array of outdoor allergens, including molds and pollens.

The atopic population develops one of these diseases or combination of them during early stage of the life. Even if one of the parents is atopic, the chances of developing atopic disorders in children increase substantially. If both father and mother are atopic, their offspring are highly sensitive to the atopic diseases.

Environmental factors like pollen season directly affect the very young individuals. For instance, kids born during pollen season are highly sensitive to allergies because of an immature and weak immune system. Pollen-triggered allergy symptoms also depend on the source and media of plant pollination.

Insects and wind transfer the plant gametes (pollens) from one place to another place.  Insects generally collect pollens from the plants bearing bright color flowers. The pollens of these plants are quite limited in number. These pollens rarely trigger allergies. On the other hand, wind-pollinated vegetation produces a large amount of pollens, causing allergies. Since pollens mainly trap in the nose, rhinitis is the main outcome. If pollens soaked in raindrops and dew, they may affect bronchi, triggering an asthma attack.

Grass pollens are the main cause of allergies. Grass pollinates during summer whereas trees in spring. Grass pollination season is relatively longer than that of trees. Birch pollen allergies are common in North America and Europe, and Asia. The birch pollens react with nut and hazel pollens. Incidences of “birch/apple syndrome” are also recorded in these areas, where soft fruit, vegetables and fresh apples trigger oral allergies. The olive pollens that react with privet cause allergies in the Mediterranean region.