There’s a lot of talk about allergies. But just what is an allergy and what causes them? Why do some people have them while others don’t? And why are people with one allergy more inclined to have many?
The immune system is set up to protect our bodies from harmful, foreign substances.
Like viruses and bacteria (dirt and germs). Sometimes the immune system doesn’t develop properly or is just oversensitive and doesn’t react right.
In these cases, it reacts to things that aren’t harmful and don’t usually cause people any problems. These things are called allergens. The term allergens is just an easier way to say "things that cause allergies".
When the oversensitive or improperly developed immune system sees these allergens, it sends out chemicals like histamine. It’s the histamines that cause the symptoms that are common with allergies.
Symptoms like itching, watery eyes, runny nose, swelling, hives or rashes. Different people have different symptoms, but the causes are the same.
The symptoms that are displayed depend on the part of the body the allergen comes in contact with. Allergens that are breathed in, like pollen or dust cause coughing or wheezing, stuffy or runny noses and an itchy 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 threatening reactions. Drug allergies tend to involve the entire body, so they have a variety of symptoms.
Learn About Allergies from our short daily flash briefings.
This tool does not provide medical advice, and is for informational and educational purposes only, and is not a substitute for professional medical advice, treatment or diagnosis. Call your doctor to receive medical advice. If you think you may have a medical emergency, please dial your local emergency response phone number.
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