Severe Allergic Reaction

What is a severe allergic reaction?

Some people can have a severe allergic reaction when they come into contact with something they are allergic to. Symptoms of the reaction, like severe swelling and trouble breathing, usually start within minutes to an hour or two after contact with the substance. In rare cases, symptoms may occur up to a few hours later. A severe allergic reaction can be life threatening.

Examples of substances that can cause some people to have a severe allergic reaction are some medicines and bee stings. Substances that cause allergy symptoms are called allergens. The medical term for a severe allergic reaction is anaphylaxis.

How does it occur?

If you have a severe allergy to a substance, contact with it makes your blood vessels leak fluid into the area around them. This can make your blood pressure drop suddenly. Because there is less blood flow, less oxygen reaches your brain and other vital organs. Since these organs do not work well when they don’t have enough oxygen, your body goes into shock. In addition, your body responds to the allergen by releasing chemicals such as histamines, which cause swelling, a red rash or hives, and severe itching.

A severe allergic reaction may be caused by:

• food--for example, peanuts or food additives
• insect stings and bites
• allergy shots
• medicines
• latex
• anesthetics
• vaccines
• in rare cases, pollens, dust, perfume, chemicals, pet dander, or other substances in the air (including the smoke from burning poison ivy or poison oak)

What are the symptoms?

Symptoms of a severe allergic reaction include:

• hives (itchy, blotchy, raised rash)
• feeling dizzy or faint
• trouble breathing, including wheezing
• trouble swallowing
• tightness in the throat or chest
• swelling of the lips, tongue, throat, or other part of the body
• nausea, vomiting, or diarrhea
• stomach cramps
• sense of impending doom
• loss of consciousness, even death

How is it diagnosed?

First, your healthcare provider will treat you for your symptoms. Once you are out of danger from any complications, then the search for the cause will begin.

Your provider will ask about your personal and family history of allergies. Your provider will ask about recent contact with substances you may be allergic to.

If you have not previously had allergy testing, when you are feeling better you may have some tests to find the cause of your allergic reaction.

How is it treated?

A severe allergic reaction needs emergency medical attention. If you think you or someone else is having a severe allergic reaction, call 911.

Treatment of yourself:

If you have severe allergies, your provider may prescribe an epinephrine emergency kit (such as EpiPen or Twinject). You will need to always carry the kit with you. It contains a ready-to-use syringe of a medicine called epinephrine. If you have a severe allergic reaction, a shot of this medicine can counteract allergy symptoms until you get medical care. You or someone with you can give you the shot. The kit is not intended as the sole treatment of an allergic reaction. Rather, it "buys" time until you can get emergency medical care.

As soon as you start having symptoms of a serious allergic reaction, call 911. Use an EpiPen if you have one. While you wait for help, lie down and raise your legs above the level of your chest to increase the blood flow to your heart and brain. If possible, remove the substance causing the reaction, such as the stinger if you were stung by a bee.

Treatment of someone else who is having a severe allergic reaction

After calling 911, check to see if the person has stopped breathing or if his or her heart has stopped beating. If so, give cardiopulmonary resuscitation (CPR) until the person is breathing or until paramedics arrive.

If the person is unconscious but breathing, gently turn him or her on their side to prevent choking if they vomit. If you saw the person lose consciousness and know it's because of a severe allergic reaction and you have been taught how to give the EpiPen, give them the shot while you wait for emergency help to arrive.

If the person is conscious and breathing, make sure he or she is lying down comfortably. If the person is not fully alert, is vomiting, or feels like vomiting, he or she needs to lie on their side to prevent choking on vomit. If the person is conscious and has a clear airway (has nothing in his or her mouth or throat), you can raise their legs above the level of their chest to increase blood flow to the heart and brain.

If possible, remove the substance causing the reaction, such as the stinger if the person was stung by a bee. Save the insect for identification, if it’s possible and safe to do so. It will be helpful to the healthcare provider.

See if there is a medical card, bracelet, or necklace that has information about allergies.

Medical treatment

When a doctor or paramedic arrives, he or she may give a shot of epinephrine (adrenaline). In addition, the healthcare provider may:

• Give drugs such as antihistamines and steroids, usually into a muscle or vein.
• Give fluids through the veins to increase fluid volume inside the blood vessels.
• Observe you in the emergency room or hospital to make sure that your blood pressure and heartbeat go back to normal. You will also be watched to make sure that the allergy symptoms don’t come back as the effect of the medicines wears off.

How long will the effects last?

The effects of a severe reaction depend on how quickly you get treatment. The symptoms may last from a few minutes to several hours. Without immediate medical treatment, a severe reaction can kill you. However, early treatment can help prevent serious complications.

A severe allergic reaction can cause brain damage, kidney failure, and death.

How can I take care of myself?

• If you are having an allergic reaction, get help right away. Do not delay.
• Tell your healthcare provider about all past allergic reactions you have had.
• Avoid foods, chemicals, and other things that have caused allergic reactions. For example, if you have a reaction to shrimp, don't eat shrimp or any food that might contain shrimp. If you have drug or food allergies, always check labels before taking any prescription or nonprescription medicines or eating any foods. If you are in a restaurant, ask about all ingredients.
• If your provider prescribes an epinephrine emergency kit, such as EpiPen or Twinject, make sure you go over the instructions for use of the medicine with your provider. Regularly check the expiration date on the kits. Carry 1 kit with you in your briefcase, sports bag, or handbag, and keep 1 at home. Don’t keep the kits in the car. The medicines may not work after they have been exposed to heat or cold.

  Be ready to give yourself a shot of the medicine if you start having an allergic reaction. Teach family members and coworkers how to help you. Think of the shot as something you can do to keep yourself alive long enough to get medical care.

• If you have contact with a substance that you have reacted to before, take diphenhydramine (Benadryl) if it is available according to your healthcare provider’s recommendation.
• Wear a bracelet or necklace that warns of your allergy and tells what to do in case of an emergency. Tell your family, friends, and co-workers what they should do if you have a severe reaction.
• Ask your healthcare provider if allergy shots are a possible treatment for you. Over time, the shots make you less sensitive to allergens and make them less harmful to you. Allergy shots may work well for insect allergies. In the past they have not worked well for food allergies, but researchers are looking for treatments that will help people overcome common food allergies, such as peanuts.
• Tell all pharmacists, healthcare providers, and dentists who treat you about any allergies you have and your reactions. Some medicines contain ingredients that might cause an allergic reaction.
• For more information, contact:

  The Food Allergy & Anaphylaxis Network (FAAN)
  Phone: (800) 929-4040
  Web site: http://www.foodallergy.org.

How can I help prevent a severe allergic reaction?

• Learn what substances cause you to have an allergic reaction and avoid those substances.
• Make sure your healthcare provider knows what you are allergic to and what your reactions have been.
• Always carry your allergy emergency kit with you. Talk with your provider about how you should use it. Teach your family and friends how to use it, too.
• Ask your healthcare provider if desensitization treatments, such as allergy shots, might help you.
• Always read labels and ask about ingredients in restaurant or cafeteria foods.
• Educate your family and friends about your allergies. Tell them how to help you avoid the things you are allergic to and how to help you if you start to have a reaction.