Childhood Allergies

Childhood Allergies – Part 2 – What are Allergies?

Childhood AllergiesThis is the second in a series of posts answering the question: “Why has there been such an astronomical rise in childhood allergies?”

Before we go into the various theories, I would like to step back and give a short lesson on allergies and immunology. I confess that I’m a total geek about this kind of thing. Immunology was absolutely one of my favorite college courses. But, since most people aren’t biology geeks, I’ll try to keep it a simpler level. If I confuse, be sure to leave a note in the comments and I’ll reply.

Let’s start with the Immune System. Your immune system functions to protect you from invading organisms, usually unfriendly bacteria, viruses, fungi, and parasites. The immune system is generally a good thing, as it serves to keep us healthy. The immune system is complex. It starts with the skin which usually acts as a physical barrier and extends to various cells that act in our defense.

A function of the lymphocytes, one of the cell types, is to produce immunoglobulins. Immunoglobulins, commonly known as antibodies, are protein molecules. They are produced in response to a particular antigen – typically a protein that is part of an invading organism. There are a number of types of immunoglobulins typically IgA, IgG, and IgE. The image at the top of this post is representative of the basic shape of an immunoglobulin or antibody; although I added a bit of color to it. The IgE antibody is the one generally associated with allergies.

So, if our immune system produces antibodies to invading organisms, what is an allergy? After all, an allergy is a reaction by the immune system. An allergy occurs when our immune system has an abnormal reaction to a generally harmless substance – such as food, pollen, pet hair, etc.

Your first exposure to any potential antigen does not usually cause a noticeable reaction. Typically, your first exposure is what activates the immune system. It thinks it has found an antigen and produces the antibodies. On subsequent exposure, the antigen will bind to the cells containing the antibody and that is when you will see an allergic reaction.

Two more points before we move on:

  1. It isn’t always the second exposure that results in an allergic reaction. An allergy can develop at a later time.
  2. This production of IgE antibodies – the allergic reaction – is what makes an allergy separate from a sensitivity.

Next up in the series – we’ll explore the eczema – food allergy connection.

This is the second in a series of blog posts answering the question: “Why has there been such an astronomical rise in childhood allergies?” To view other posts:

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