There’s a lot of talk about allergies. But just whatis an allergy and what causes them? Why do some peoplehave them while others don’t? And why are people withone allergy more inclined to have many?

The immune system is set up to protect our bodies fromharmful, foreign substances. Like viruses and bacteria(dirt and germs). Sometimes the immune system doesn’tdevelop properly or is just oversensitive and doesn’treact right.

In these cases, it reacts to things that aren’tharmful and don’t usually cause people any problems.These things are called allergens. The term allergensis just an easier way to say “things that causeallergies”.

When the oversensitive or improperly developed immunesystem sees these allergens, it sends out chemicalslike histamine. It’s the histamines that cause thesymptoms that are common with allergies.

Symptoms like itching, watery eyes, runny nose,swelling, hives or rashes. Different people havedifferent symptoms, but the causes are the same.

The symptoms that are displayed depend on the part ofthe body the allergen comes in contact with. Allergensthat are breathed in, like pollen or dust causecoughing or wheezing, stuffy or runny noses and anitchy nose and throat.

Plant allergies usually come in contact with the skin,so they cause rashes.

Food allergies usually result in nausea, vomiting,stomach pains or in severe cases, life threateningreactions. Drug allergies tend to involve the entirebody, so they have a variety of symptoms.