Severe Allergic Reaction (Anaphylaxis)

What is anaphylaxis?

Anaphylaxis is a severe allergic reaction that may occur when you come into contact with something you are allergic to (called an allergen). Symptoms of the reaction usually start within minutes to an hour or two after contact with the allergen. In rare cases, symptoms may occur up to 4 hours later. Examples of substances that can cause some people to have a severe allergic reaction are penicillin and bee stings.

How does it occur?

If you have a severe allergy to a substance, contact with that allergen causes your blood vessels to leak fluid into the area around them. As a result, your blood pressure may drop suddenly. Because there is less blood flow, less oxygen reaches your brain and other vital organs. Since these organs do not function properly with a lack of oxygen, your body goes into shock. In addition, your body responds to the allergen by releasing chemicals such as histamines, which cause swelling of the skin, a red rash, and severe itching.

Complications of anaphylaxis can include brain damage, kidney failure, and death.

Anaphylaxis can be caused by an allergic reaction to:

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

What are the symptoms?

Symptoms of a severe allergic reaction include:

• itchy, blotchy, raised rash called hives
• feeling dizzy or faint
• trouble breathing, including wheezing
• trouble swallowing
• tightness in the throat or chest
• nausea, vomiting, or diarrhea
• stomach cramps
• swelling of the lips, tongue, throat or another part of the body
• red, watery eyes
• sense of impending doom
• hoarse voice
• loss of consciousness, even death.

How is it diagnosed?

If you are conscious, your healthcare provider will ask you about contact with substances you may be allergic to. Then your provider will examine you for symptoms of shock by checking your:

• blood pressure
• pulse and heart rate
• breathing
• skin condition and color
• alertness and mental status.

Your provider may recommend tests to determine the cause of your condition and its seriousness.

How is it treated?

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

If you have severe allergies, your provider may prescribe an EpiPen emergency kit for you to carry with you. The kit contains a ready-to-use syringe of epinephrine. If you start having a severe allergic reaction, you or someone else can give you a shot of this medicine to counteract the allergy symptoms until you get medical care. The kit is not intended as the sole treatment of an allergic reaction. Rather, it "buys" time while you wait for emergency help.

Treatment of yourself:

As soon as you start having symptoms of a serious allergic reaction, call 911 and use the EpiPen to give yourself a shot of medicine to counteract the reaction until medical help arrives. 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 conscious and breathing, make sure he or she is lying down comfortably. If the person is conscious and has a clear airway (has nothing in his or her mouth or throat), raise the person's legs above the level of the chest to increase blood flow to the heart and brain. If the person is vomiting or feels like vomiting, he or she needs to lie on their side to prevent choking on vomit.

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 personnel to arrive.

If possible, remove the substance causing the reaction, such as the stinger if the person was stung by a bee.

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 or cortisonelike drugs, usually into a muscle or vein.
• Give fluids through the veins to increase fluid volume inside the blood vessels.
• Hospitalize you for observation to be sure that your blood pressure and heartbeat go back to normal levels and that the symptoms do not come back.

How long will the effects last?

How long the effects of anaphylaxis last depends on how quickly you get treatment. The symptoms may last from a few minutes to several hours. Without immediate medical treatment, the result can be death, but early treatment can help prevent serious complications.

How can I take care of myself?

• If you are having an allergic reaction, do not delay getting help.
• Tell your healthcare provider about all past allergic reactions you have had.
• Avoid foods, chemicals, and other substances that have caused allergic reactions. For example, if shrimp causes an allergic reaction, don't eat shrimp or any food that might contain shrimp. If you have drug or food allergies, always check labels before taking medicines or eating foods. This includes nonprescription medicines.
• Ask your healthcare provider to prescribe medicine kits for treating anaphylaxis. Make sure you review the instructions with your provider. Regularly check the expiration dates on the kits. Carry one kit with you in your briefcase, sports bag, or handbag, and keep one at home. Do not keep kits in the car. The medicines are not stable in heat or cold and will not work well if they get too hot or cold.
• Be prepared to give yourself a shot in case of an emergency. Teach family members and coworkers how to help you if you have a severe reaction. Think of the shot as something you can do to keep yourself alive long enough to get medical attention.
• If you come in contact with a substance to which you have had a previous reaction, take diphenhydramine (Benadryl) if it is available.
• 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 allergic reaction.
• Ask your healthcare provider if immunotherapy is a possible treatment for you. Immunotherapy gradually exposes your immune system to the toxic substance to make it less harmful to you. Immunotherapy may be very effective for insect allergies but not for food allergies.
• Tell all pharmacists, healthcare providers, and dentists who treat you about any allergies you have. Some medicines contain ingredients that may cause you to have 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 substance causes your reaction and avoid that substance. Ask your healthcare provider if desensitization treatments, such as allergy shots, might help you.