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Allergies Health Center

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Symptoms of an Allergic Reaction

Symptoms of an allergic reaction vary depending on the body part affected and the severity of the reaction. Some reactions affect many areas, while others affect just one area. Reactions to the same allergen vary by individual.

Symptoms of an allergic reaction include any, some, or many of the following:

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Anaphylaxis is serious, potentially life-threatening allergic reaction which is rapid, or sudden, and potentially life-threatening.

One sign of anaphylaxis is shock. Shock has a very specific meaning in medicine: the organs of the body are not getting enough blood because of dangerously low blood pressure. This drop in blood pressure happens when the large blood vessels suddenly expand. If the drop in blood pressure is sudden and drastic, it can lead to unconsciousness, even cardiac arrest and death.

The person in shock may be pale or red, sweaty or dry, confused, anxious, or unconscious.

Breathing may be difficult or noisy, or the person may be unable to breathe.

If you have severe allergies, you should keep two epinephrine injection kits with you at all times and readily available. If you experience any sign of anaphylaxis, do not hesitate to use the epinephrine auto-injector, even if those symptoms do not appear to be allergy related. Using the pen as a precaution will not harm you. Dial 911 after injecting.


WebMD Medical Reference

Reviewed by Jennifer Robinson, MD on October 21, 2015

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