An allergic reaction is actually a reaction, or overreaction, of the body's immune system to an allergen like dust, mold, mildew, pet dander, medication, food or other triggers. In people with allergies, the body's immune system sees these allergens as invaders, initiating reactions and releasing substances that can wind up causing a broad array of uncomfortable symptoms.
Symptoms can vary from one person to another and may include:
nasal congestion or runny nose
watery or itchy eyes
itchy or scratchy throat
hives or rash
In a few instances, severe allergic reactions can cause a condition called anaphylaxis that can result in significant difficulty with breathing as well as seizures and even death. People who are known to have severe reactions usually carry an injectable medicine that can be quickly administered if they come in contact with the allergen to help reduce the risk of anaphylaxis.
A personal and family medical history including your current symptoms is an important part of the diagnosis, and in some cases, skin testing may also be used to identify allergens. Skin testing involves applying an array of allergens to the skin surface or just beneath the surface of the skin, then evaluating the reactions after a brief period of time has passed.
Depending on your symptoms, over-the-counter or prescription medications like antihistamines may be used to control many symptoms of allergies. When reactions are more severe or problematic, allergy shots (or immunotherapy) may be used to help desensitize the immune system to help prevent allergic reactions from occurring. Avoiding known allergens is also important for reducing symptoms.