All you need to know about Allergies

All that you wanted to know about allergies and didn't know whom to ask.

Allergies refer to immune hyperactivity toward certain substances that our bodies recognise as harmful. When the body identifies a particular environmental or dietary material as ‘foreign’ or a threat, it triggers a chain reaction or ‘immune response’ that attacks the concerned cells in an effort to eliminate the threat. This is what we see as allergic symptoms.

Children generally outgrow allergies with age. But some people have chronic (long-term) allergies and even those that worsen with each episode. Some are seasonal, while others are location-specific. Therefore, there is no definite timeline.

Substances that trigger allergic reactions are referred to as ‘allergens’.

The prevalence of certain allergens is dependent on environmental factors such as geographical location, season, climatic changes, and air currents, as well as human/ industrial activities in the vicinity. The best example of this is pollen since only pollen from particular plants accounts for a majority of the cases. Therefore, obviously, all the above-mentioned factors are essential for a specific plant species to thrive in a particular location and time.

Allergens can be classified into different categories based on their origin.

Some food ingredients, drugs, and daily-use products can cause allergies in vulnerable populations. So do household conditions (molds) and common insects, such as cockroaches


Trivia: Is ‘dust allergy’ really caused by dust particles? Check this post for the answer.

Interestingly, an episode of allergic symptoms can be triggered or aggravated by stress and anxiety, as well as some viral infections, as they can weaken the immune system.

Figure 1: Different types of allergens

Who is vulnerable to allergies?

These reactions and their severity are individual-specific as they are largely dependent on the genetic makeup. Thus, the tendency to develop allergies can run in the family, though the triggering substance may differ between the members.

It is possible for an allergy-free person to develop new allergies when they move places. Also, multiple allergies and interactions between allergies (with simultaneous exposure to the triggers) are common in the vulnerable population. Therefore, knowing the family history is important in allergy diagnosis.

Years of research have helped us identify a few risk/ protective factors (particularly during early childhood) that strongly influence the allergy profile or likelihood of allergy development later in life.

Do allergies start abruptly? Are there any warning signs?

An allergic reaction is comparable to a post-vaccination immune response. It may seem abrupt but it is a gradual process that is invisible to us.