Health Conditions

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Allergic reactions

Definition

Allergic reactions are sensitivities to substances, called allergens, that are contacted through the skin, inhaled into the lungs, swallowed, or injected.


Causes

Common allergens include:

  • Animal dander
  • Bee stings or stings from other insects
  • Foods, especially nuts, fish, and shellfish
  • Insect bites
  • Medications
  • Plants
  • Pollens

Symptoms

Common symptoms of a mild allergic reaction include:

  • Hives (especially over the neck and face)
  • Itching
  • Nasal congestion
  • Rashes
  • Watery, red eyes

Symptoms of a moderate or severe reaction include:

  • Cramps or pain in the abdomen
  • Chest discomfort or tightness
  • Diarrhea
  • Difficulty breathing
  • Difficulty swallowing
  • Dizziness or lightheadedness
  • Fear or feeling of apprehension or anxiety
  • Flushing or redness of the face
  • Nausea and vomiting
  • Swelling of the face, eyes, or tongue
  • Weakness
  • Wheezing
  • Unconsciousness

Prevention

  • Avoid triggers such as foods and medications that have caused an allergic reaction, even a mild one, in the past. This includes asking detailed questions about ingredients when you are eating away from home. Also carefully examine ingredient labels.
  • If you have a child who is allergic to certain foods, introduce one new food at a time in small amounts so you can recognize an allergic reaction.
  • People who know that they have had serious allergic reactions should wear a medical ID tag.
  • If you have a history of serious allergic reactions, carry emergency medications (such as diphenhydramine and injectable epinephrine or a bee sting kit) according to your health care providerís instructions.
  • Do not use your injectable epinephrine on anyone else. They may have a condition (such as a heart problem) that could be negatively affected by this drug.