Allergic Reaction (cont.)
Allergic Reaction Causes
Almost anything can trigger an allergic reaction.
- The body's immune system involves the white blood cells, which produce antibodies.
the body is exposed to an antigen (a foreign body such as pollen that can trigger an immune response), a complex set of reactions begins.
- The white blood
cells produce an antibody specific to that antigen. This is called "sensitization."
- The job of the antibodies is to help white blood cells detect
and destroy substances that cause disease and sickness. In allergic reactions, the antibody belongs to the class of immunoglobulins known as immunoglobulin E or
- This antibody type promotes production and release of chemicals and hormones called "mediators."
- Mediators have effects on
local tissue and organs in addition to activating more white blood cell defenders. It is these effects that cause the symptoms of the reaction.
- Histamine is
one of the better-known allergy mediators produced by the body.
- If the release of the mediators is sudden or extensive, the allergic reaction may also be
sudden and severe, and anaphylaxis may occur.
- Allergic reactions are unique for each person. Reaction time to allergens can vary widely. Some
people will have an allergic reaction immediately; for others, it will take time to develop.
- Most people are aware of their particular allergy triggers and
- There are more than 160 allergenic foods. Certain foods are common allergens, including peanuts, strawberries, shellfish, shrimp, dairy, and
- Babies can also have food
allergies. Common foods that can cause allergic reactions in babies include milk, eggs, nuts, and soy. People should talk to their child's pediatrician if they
are concerned about food allergies in their baby.
- Food intolerance is not the same as food allergies. Allergies are an immune system response, while food intolerance is a digestive system response in
which a person is unable to properly digest or break down a particular food.
- Vaccines and medications (antibiotics such as penicillin and amoxicillin, aspirin, ibuprofen, iodine), general anesthesia and
local anesthetics, latex rubber (such as
in gloves or condoms), dust, pollen,
mold, animal dander, and poison
ivy are well-known allergens. Other known allergens can include detergents, hair dyes, cosmetics, and the ink in
- Bee stings, fire ant stings, penicillin, and peanuts are known for causing dramatic reactions that can be serious and involve the whole
- Minor injuries, hot or cold temperatures,
exercise, stress, or emotions may trigger allergic
- Sun exposure may cause allergic reactions in some people, often referred to as "sun poisoning."
- Often, the specific
allergen cannot be identified unless someone has had a similar reaction in the past.
- Allergies and the tendency to have allergic reactions run in some
- Many people who have one trigger tend to have other triggers as well.
- Risk factors for allergic reactions include certain medical
conditions that can make a person more likely to have allergic reactions:
- Severe allergic
reaction in the past
- Lung conditions that affect breathing, such as chronic obstructive
pulmonary disease (COPD)
- Frequent infections of the nasal sinuses, ears, or respiratory tract
- Sensitive skin, especially sufferers of eczema
Medically Reviewed by a Doctor on 9/28/2015
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