Banning nuts on planes and in schools may seem like hysteria, but there’s good reason: allergies are becoming more common. And you may not realise how you’re affected
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What are allergies anyway?
If your summer months are blighted by congestion, sneezing and a runny nose, you might think your immune system has gone into overdrive, or that it is especially good at its job. But unfortunately it’s not that simple.
Allergies are caused by the immune system mistakenly reacting to certain innocuous molecules from the outside world. These can be part of anything from cat skin to certain foods (see “The most common allergies”, overleaf). Any molecule capable of doing this is called an allergen. Although allergens pose no real danger to our bodies, their structures are recognised as a threat by some people’s antibodies – immune proteins on the lookout for harmful invaders.
Allergies are on the rise – and you might even be affected by one without realising. So how can we best deal with the allergy explosion?
Allergies involve a special class of antibodies called immunoglobulin E (IgE). Different IgE antibodies detect different allergens. When this happens, the antibodies trigger immune cells to release histamine and other inflammatory chemicals, leading to those nasty symptoms, which under normal circumstances would be a useful defence against invading organisms.
This is a highly primed defence mechanism. IgE antibodies bind to immune cells about 1000 times more tightly than any other class of antibody. This means they are usually already attached to an immune cell, and the whole system is ready to respond as soon as an allergen is …
–Credit: New Scientist – Home