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Allergic Reaction, Severe, Discharge Information

What is a severe allergic reaction?

An allergic reaction is your body’s reaction to a substance that is normally harmless. A substance that triggers your allergy is called an allergen. Allergens can include foods, insect stings or bites, medicines, chemicals, pollen, dust, pet dander, smoke, or other things in your environment.

Symptoms of an allergic reaction usually start within minutes to an hour or two after contact with the allergen. Allergic reactions can be mild or more severe. A severe allergic reaction can be life threatening. You may have severe swelling of the lips, tongue, or throat; itching; skin rash; hives; or trouble breathing. Your blood vessels may leak fluid into the area around them. This can make your blood pressure drop suddenly and cause you to go into shock. The medical term for a severe allergic reaction is anaphylaxis.

How can I take care of myself when I go home?

How long it takes to get better depends on the cause of your severe allergic reaction, your treatment, how well you recover, your overall health, and any complications you may have.


  • Your provider will give you a list of your medicines when you leave the hospital.
    • Know your medicines. Know what they look like, how much you should take each time, how often you should take them, and why you take each one.
    • Take your medicines exactly as your provider tells you to.
    • Carry a list of your medicines in your wallet or purse. Include any nonprescription medicines and supplements on the list.
  • Your provider may prescribe medicine to:
    • Help relax your airways
    • Reduce swelling in the airways
    • Reduce your body’s response to the allergen
  • Ask your healthcare provider about the causes of your allergy and what to do when you have an allergic reaction. Ask your provider about carrying an injection kit of epinephrine, or other medicine to treat your allergic reaction. You can use it to treat yourself immediately if you have a severe allergic reaction.


  • Follow your provider’s instructions for follow-up appointments and routine tests.
  • Keep appointments for all routine testing you may need.
  • Talk with your provider about any questions or fears you have.

Diet, Exercise, and Other Lifestyle Changes

  • Follow the treatment plan your healthcare provider prescribes.
  • Get plenty of rest while you’re recovering. Try to get at least 7 to 9 hours of sleep each night.
  • Eat a healthy diet.
  • Drink enough fluids to keep your urine light yellow in color, unless you are told to limit fluids.
  • Exercise as your provider recommends.
  • Don’t smoke.
  • Ask your healthcare provider if there are foods or medicines you should avoid.
  • Carry an ID (such as a card or bracelet) that says you have a severe allergy, in case of an emergency.
  • It’s good for your family to know about your allergy. Make sure your family members know what to do if you have a severe allergic reaction.

Call emergency medical services or 911 if you have new or worsening:

  • Trouble breathing
  • Drooling or trouble swallowing
  • Fainting
  • Breathing does not get easier with medicine

Do not drive yourself if you have any of these symptoms.

Call your healthcare provider if you have new or worsening:

  • Hives
  • Itching
  • Lightheadedness
  • Skin rash
  • Coughing with chest tightness
  • Symptoms that happen more often or are worse than normal
Developed by RelayHealth.
Acute Care Advisor 2015.1 published by RelayHealth.
Last modified: 2014-07-30
Last reviewed: 2014-07-31
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.

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