Anaphylaxis is a severe allergic reaction that can be life threatening. This reaction can happen in a few minutes, or a few hours after exposure to what you are allergic to. Some people are more prone to this than others.

The symptoms of an anaphylactic reaction may seem similar to other allergic reactions at first. If this has happened to you in the past, don't let the early mild symptoms, such as a rash, hives and itching, mislead you. Your reaction can worsen very quickly and become much more severe and life threatening within minutes.

More severe symptoms include:

  • Trouble swallowing, feeling like your throat is closing

  • Trouble breathing, wheezing

  • Cool, moist or pale (blue in color) skin

  • Hoarse voice or trouble speaking

  • Nausea, vomiting, diarrhea, stomach cramps, or pain

  • Feeling faint or lightheaded, rapid heart rate, low blood pressure

  • Feeling dizzy or confused

  • Becoming very drowsy, poorly responsive, or trouble awakening

  • Seizure

Sometimes the cause may be obvious, like knowing you are allergic to peanuts. To help identify your allergen, remember:

  • When it started

  • What you were doing at the time or just before that

  • Any activities you were involved in

  • Any new products or contacts

 Here are some common causes, but remember almost anything can cause a reaction, and you may not even be aware that you came into contact with one of these things.

  • Foods such as shrimp, shellfish, peanuts, milk products, gluten, eggs; also colorings, flavorings, additives

  • Insect bites or stings such as bees, wasps, hornets, or fire ants

  • Medicines such as penicillin, sulfa, aspirin, ibuprofen; any medicine can cause a reaction


  • Latex such as in gloves, clothes, toys, balloons, or some tapes (some people allergic to latex may also have problems with foods like bananas, avocados, kiwi, papaya, or chestnuts)

If you are exposed to the same substance again, you may have the same or more severe reaction. Treatment for anaphylaxis is epinephrine (adrenalin). This is available by prescription as a self-injectable pen. If the cause of your reaction is known, you should avoid exposure in the future. If the cause is not known, follow up with your healthcare provider for special testing to determine what you are allergic to.

Allergies to other substances such as dust, pollens, and animals rarely cause anaphylaxis.

Home care

Once you are stabilized in the emergency room and it is safe for you to go home, watch for any worsening of symptoms. You may need to be treated again.


Injectable epinephrine

One of the key tools in treating anaphylaxis is early use of epinephrine. If you had a severe allergic or anaphylactic reaction, the healthcare provider may prescribe a self- injectable epinephrine kit consisting of two epinephrine injectors. If this was prescribed, carry both epinephrine injectors at all times. It can be life saving. Epinephrine can help stop the progression of an allergic reaction. Its effects are brief, so after you use the medicine, it is still very important to call 911 and get to an emergency room.

When to use injectable epinephrine. Use the epinephrine if you have a history of severe reactions or any of the following symptoms:

  • Swelling in your mouth or throat 

  • Trouble speaking or swallowing

  • Trouble breathing

  • Feeling faint, low blood pressure, or becoming drowsy or poorly responsive

  • Worsening rash

How to use injectable epinephrine:

  • Hold the syringe firmly in your hand with the orange (or black) needle end away from your thumb

  • Be careful not to stick your fingers or hand with the needle.

  • At the opposite end, pull off the activation cap- the blue or grey tab

  • Holding the syringe tightly, jab it into the outer part of your upper thigh. This is one of the softest, fleshiest parts of the upper leg, and is not near a major blood vessel or nerve. Be careful not to inject it into your hip or any place that there is a pulse.

  • You can inject it through pants, but make sure not to inject it into the seam of the pants.

  • Don't pull it out right away. Try to hold the needle in place for 10 seconds.

  • Massage the spot for a few seconds or as directed by your healthcare provider.

  • If you are injecting it in someone else or a child, try to hold them or their leg still. If they jerk or yank their legs away as you are doing it, it can cause a cut on their leg.

You may feel shaky, jittery, nervous, and anxious after the injection. Although it is difficult, try to relax. This is a side effect of the epinephrine, and should stop after a few minutes 


  • Call 911 or get to the emergency room immediately after using the epinephrine. Its affect will wear off, and you may have a second reaction. This could even happen hours later.

  • If your symptoms start to return 5-15 minutes after using your epinephrine injector and help has not arrived yet, use the second injector.

  • Never intentionally eat, use, or expose yourself to the substance that caused the anaphylactic reaction.  Nothing is foolproof, including the injectable epinephrine.

Other medicines

The healthcare provider may prescribe medicine to relieve swelling, itching, and pain. Follow the provider's instructions when using this medicine. 

  • Oral diphenhydramine is an antihistamine available at drug and grocery stores. Unless a prescription antihistamine was given, diphenhydramine may be used to reduce itching if large areas of the skin are involved. It may make you sleepy, so be careful using it in the daytime or when going to school, working, or driving. 

  • Don't use diphenhydramine cream on your skin, because in some people it can cause a further reaction.

  • You may use over-the-counter acetaminophen or ibuprofen to control pain, unless another pain medicine was prescribed.

  • If you were prescribed any medicines to prevent symptoms from returning, be sure to take them exactly as directed.

General care

  • Rest at home for the next 24 hours.

  • Don't use tobacco or drink alcohol. These may worsen your symptoms.

  • If you know what caused your reaction today, stay away from that in the future. Let your family members, friends and personal healthcare provider know about your allergic reaction.

  • If your allergy was to food, learn how to read food labels so you can check for that ingredient. If a product doesn't have a label, it's best to avoid it.

  • Consider carrying an ID card or getting a medical alert bracelet to inform medical personnel of your condition in case you can't tell them.

  • Tell all of your healthcare providers that you had an anaphylactic reaction. Make sure the information is added to your medical records.

Follow-up care

Follow up with your healthcare provider or as advised if you are not improving over the next 1 to 2 days.

Call 911

Call 911 if any of these occur:

  • Trouble breathing or swallowing, wheezing

  • Hoarse voice or trouble speaking

  • Chest pain

  • Confused

  • Very drowsy or trouble awakening

  • Fainting or loss of consciousness

  • Rapid heart rate

  • Vomiting blood, or large amounts of blood in stool

  • Seizure

  • Swelling in the eyes, mouth, face, or tongue

  • Dizziness or weakness

  • Cool, moist, or pale (blue in color) skin

  • Nausea, vomiting, diarrhea, stomach cramps, or abdominal pain

When to seek medical advice

Call your healthcare provider right away or seek medical attention right away if any of these occur:

  • Your symptoms get worse

  • New symptoms develop

  • Symptoms don't go away or come back

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