Symptoms of an Allergic Reaction

Symptoms of an allergic reaction vary. It depends on which parts of your body get affected and how severe your reaction is.

Two people could have very different symptoms from the same allergen.

You could haveskin issues, including:

  • Redness
  • Itching
  • Swelling
  • Blistering
  • Weeping
  • Crusting
  • Rash
  • Eruptions
  • Itchy bumps or welts called hives

You could have other problems, too:


That's the name for an allergic reaction that's sudden and life-threatening.

One symptom of anaphylaxis is shock. When you’re in shock, the organs of your body don’t get enough blood, because your blood pressure is dangerously low. If the drop in BP is sudden and drastic, it can lead to unconsciousness, cardiac arrest, or death.

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

Their breathing may be labored or noisy, or they may be unable to breathe.

If you have severe allergies, you should keep two epinephrine injection kits with you and within easy reach at all times. If you feel like anaphylaxis may be happening, call 911 and use your epinephrine auto-injector right away, even if you’re not sure the symptoms are allergy-related.

WebMD Medical Reference Reviewed by Sabrina Felson, MD on March 07, 2020



William Larry Haith, DO, FAAEM, Consulting Staff, Department of Emergency Medicine, Southern Maine Medical Center.
American Academy of Allergy, Asthma & Immunology.

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